sys-libs/glibc: pull 2.30 and 2.31 upstream patches, bug #708758

Among other things patches to fix posix_spawn syscall on mips
and other targets..

Reported-by: Joshua Kinard
Closes: https://bugs.gentoo.org/708758
Package-Manager: Portage-2.3.89, Repoman-2.3.20
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

3 files changed, 2985 insertions, 0 deletions

diff --git a/sys-libs/glibc/Manifest b/sys-libs/glibc/Manifest
index 3e9b46ae103f..abcf78681bc8 100644
--- a/sys-libs/glibc/Manifest
+++ b/sys-libs/glibc/Manifest
@@ -17,7 +17,9 @@ DIST glibc-2.29-patches-8.tar.xz 102712 BLAKE2B 49aacff358c0f8499c444e73eec92f40
 DIST glibc-2.29.tar.xz 16515488 BLAKE2B b754e6825176538a2b8ca03fce014f0d87d333dc4d038bf0cda5ee8a2f484cd3ce93ad78ec126737e093ab64b55ceedf04cd08aecb4f8041daaa329e99717afa SHA512 146bc0769fe853d9edbf93cea7f74c5b3d84d69cb7614c62588e7acdecd1ec789a9d8949f3e8b99f8f36f2ccac740a003bed94f32b07817baf780b06cfeb6ed0
 DIST glibc-2.30-patches-3.tar.xz 20412 BLAKE2B 8cd588284bf07985262a0289d8cbae03b0a75c48110fed6152c0431dc4f729a9695df910b1521a6072e9736b26145bf372d5b60163f64f4556f17f2f9f223e11 SHA512 0da9107518117a1cf901d282f2b84a2f4780130ab9eb7025ffd8b7e629aa6fd5f05b293dd49fc3c300bc2e74e7f81fc1f8a7cb12428b2be086a160d429715758
 DIST glibc-2.30-patches-4.tar.xz 32428 BLAKE2B 7bdcf6f64b22d19b1ef79f466ed0c6e7a289900fbde46eec2a0f4c5458f2088928c1c3f7534eb9794659598d39d2bca21e0922d0cd0f8a459e744abe9197807c SHA512 a80c3a304bcb1acf3a71e5f55782c8aed09747139d6f554bd81b66cef77fcdf33fb943a30cc29e0b9f34cc3d005b08f11f74365b3f9ab32754ce63cbc530ad46
+DIST glibc-2.30-patches-5.tar.xz 62504 BLAKE2B 19797021000cbf0951144aa7d72b3a16c8e21677f3af8a34dba2813d1547b9773d50412492dec9c0be50c4734fdc49459a482bb2724f06bbe0be4729f19aff28 SHA512 58567963b3802aa3f51a4a462557b89fc46c930b3a0613536e650a66f95cadaa96305a2ba0d59acf2c959ceda64aa7089e86b60cd0e3e68af68612c38c96b9d6
 DIST glibc-2.30.tar.xz 16576920 BLAKE2B bd5aae4c9854f40785b91f83c3b632de6d48d811027ddfe61651cb1bc617db8017d7914c23a770cdd3feed06fcc316da841eea916cdba54179e7eace4ea45484 SHA512 37483990cd653685873e96c45dd1651b32b441b6d7919a68ebe3bae31a0c3f7ce183fc9b110f0b268b353f80312f18370559a1e7aecea0e5aa755c8f2aef1d6b
 DIST glibc-2.31-patches-1.tar.xz 17796 BLAKE2B ba843ec675b094de63e0d8e76f8583f5a930cc355825aafd013aa650b57c766051ffb1825da8bf46290cb797cf4a7ca1d553e8f8ad3c5518bf499bedd98f1414 SHA512 cdf1238391c2e7973b0d82e37672b49205a273c5d2b1df2b47aba710f7cc5fbebf4fe76af5dd219327e22de62e1ff1c7c36092952a5a80ed6276f869e40dc718
+DIST glibc-2.31-patches-2.tar.xz 23736 BLAKE2B 181ba7f774e2964efdbe6f9f0540c27e18afe76854efcad3be5e5c277cf2e671d0f21752d1d42cb82f1e60a58f76f89a4997c12b74585f88ecbab85dff459c63 SHA512 1e9ae2e0cfffd80cc7219a7f989e18987b0ecaaa6e92516f823c7f3febb8fb5c86d8d9c3d9fecb98fdda699f6d7b00660d6ca3f2fee84db60f16a76d723d0b7e
 DIST glibc-2.31.tar.xz 16676764 BLAKE2B 91df1792345f157265eae405185a81fd4b8ce36d4c2388f44b0d5b1ae38174ea374cbc909cd260770b9f38ea58051da13766d4fa22abf41c2d4a2493257b179b SHA512 735e4c0ef10418b6ea945ad3906585e5bbd8b282d76f2131309dce4cec6b15066a5e4a3731773ce428a819b542579c9957867bb0abf05ed2030983fca4412306
 DIST glibc-9999-patches-15.tar.xz 17792 BLAKE2B fe351b7c71418a4707c96fbc6832f831947515bb2ce01fcfa9a9ea410f543a50b8c013e26f10587b283acbab4e988272e8db770112b2961b11c89b20b4a408f7 SHA512 37db45d1d04ad1130319a58d04774a2ada0f026bacd444625782b4dcf5a98a7019a17e132dd1e497968f43fde2c974bbe09a41e164831769a9e95bc8e2117103
diff --git a/sys-libs/glibc/glibc-2.30-r4.ebuild b/sys-libs/glibc/glibc-2.30-r4.ebuild
new file mode 100644
index 000000000000..807c5b3944de
--- /dev/null
+++ b/sys-libs/glibc/glibc-2.30-r4.ebuild
@@ -0,0 +1,1490 @@
+# Copyright 1999-2020 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+PYTHON_COMPAT=( python3_{6,7,8} )
+
+inherit python-any-r1 prefix eutils toolchain-funcs flag-o-matic gnuconfig \
+	multilib systemd multiprocessing
+
+DESCRIPTION="GNU libc C library"
+HOMEPAGE="https://www.gnu.org/software/libc/"
+LICENSE="LGPL-2.1+ BSD HPND ISC inner-net rc PCRE"
+SLOT="2.2"
+
+EMULTILIB_PKG="true"
+
+if [[ ${PV} == 9999* ]]; then
+	EGIT_REPO_URI="https://sourceware.org/git/glibc.git"
+	inherit git-r3
+else
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sh ~sparc ~x86"
+	SRC_URI="mirror://gnu/glibc/${P}.tar.xz"
+fi
+
+RELEASE_VER=${PV}
+
+GCC_BOOTSTRAP_VER=20180511
+
+# Gentoo patchset
+PATCH_VER=5
+PATCH_DEV=slyfox
+
+SRC_URI+=" https://dev.gentoo.org/~${PATCH_DEV}/distfiles/${P}-patches-${PATCH_VER}.tar.xz"
+SRC_URI+=" multilib? ( https://dev.gentoo.org/~dilfridge/distfiles/gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz )"
+
+IUSE="audit caps cet compile-locales +crypt custom-cflags doc gd headers-only +multiarch multilib nscd profile selinux +ssp +static-libs suid systemtap test vanilla"
+
+# Minimum kernel version that glibc requires
+MIN_KERN_VER="3.2.0"
+
+# Here's how the cross-compile logic breaks down ...
+#  CTARGET - machine that will target the binaries
+#  CHOST   - machine that will host the binaries
+#  CBUILD  - machine that will build the binaries
+# If CTARGET != CHOST, it means you want a libc for cross-compiling.
+# If CHOST != CBUILD, it means you want to cross-compile the libc.
+#  CBUILD = CHOST = CTARGET    - native build/install
+#  CBUILD != (CHOST = CTARGET) - cross-compile a native build
+#  (CBUILD = CHOST) != CTARGET - libc for cross-compiler
+#  CBUILD != CHOST != CTARGET  - cross-compile a libc for a cross-compiler
+# For install paths:
+#  CHOST = CTARGET  - install into /
+#  CHOST != CTARGET - install into /usr/CTARGET/
+#
+export CBUILD=${CBUILD:-${CHOST}}
+export CTARGET=${CTARGET:-${CHOST}}
+if [[ ${CTARGET} == ${CHOST} ]] ; then
+	if [[ ${CATEGORY} == cross-* ]] ; then
+		export CTARGET=${CATEGORY#cross-}
+	fi
+fi
+
+# Note [Disable automatic stripping]
+# Disabling automatic stripping for a few reasons:
+# - portage's attempt to strip breaks non-native binaries at least on
+#   arm: bug #697428
+# - portage's attempt to strip libpthread.so.0 breaks gdb thread
+#   enumeration: bug #697910. This is quite subtle:
+#   * gdb uses glibc's libthread_db-1.0.so to enumerate threads.
+#   * libthread_db-1.0.so needs access to libpthread.so.0 local symbols
+#     via 'ps_pglobal_lookup' symbol defined in gdb.
+#   * 'ps_pglobal_lookup' uses '.symtab' section table to resolve all
+#     known symbols in 'libpthread.so.0'. Specifically 'nptl_version'
+#     (unexported) is used to sanity check compatibility before enabling
+#     debugging.
+#     Also see https://sourceware.org/gdb/wiki/FAQ#GDB_does_not_see_any_threads_besides_the_one_in_which_crash_occurred.3B_or_SIGTRAP_kills_my_program_when_I_set_a_breakpoint
+#   * normal 'strip' command trims '.symtab'
+#   Thus our main goal here is to prevent 'libpthread.so.0' from
+#   losing it's '.symtab' entries.
+# As Gentoo's strip does not allow us to pass less aggressive stripping
+# options and does not check the machine target we strip selectively.
+
+# We need a new-enough binutils/gcc to match upstream baseline.
+# Also we need to make sure our binutils/gcc supports TLS,
+# and that gcc already contains the hardened patches.
+BDEPEND="
+	${PYTHON_DEPS}
+	>=app-misc/pax-utils-0.1.10
+	sys-devel/bison
+	!<sys-devel/bison-2.7
+	!<sys-devel/make-4
+	doc? ( sys-apps/texinfo )
+"
+COMMON_DEPEND="
+	gd? ( media-libs/gd:2= )
+	nscd? ( selinux? (
+		audit? ( sys-process/audit )
+		caps? ( sys-libs/libcap )
+	) )
+	suid? ( caps? ( sys-libs/libcap ) )
+	selinux? ( sys-libs/libselinux )
+	systemtap? ( dev-util/systemtap )
+"
+DEPEND="${COMMON_DEPEND}
+	test? ( >=net-dns/libidn2-2.0.5 )
+"
+RDEPEND="${COMMON_DEPEND}
+	sys-apps/gentoo-functions
+"
+
+RESTRICT="!test? ( test )"
+
+if [[ ${CATEGORY} == cross-* ]] ; then
+	BDEPEND+=" !headers-only? (
+		>=${CATEGORY}/binutils-2.24
+		>=${CATEGORY}/gcc-6
+	)"
+	[[ ${CATEGORY} == *-linux* ]] && DEPEND+=" ${CATEGORY}/linux-headers"
+else
+	BDEPEND+="
+		>=sys-devel/binutils-2.24
+		>=sys-devel/gcc-6
+	"
+	DEPEND+=" virtual/os-headers "
+	RDEPEND+="
+		>=net-dns/libidn2-2.0.5
+		vanilla? ( !sys-libs/timezone-data )
+	"
+	PDEPEND+=" !vanilla? ( sys-libs/timezone-data )"
+fi
+
+#
+# Small helper functions
+#
+
+is_crosscompile() {
+	[[ ${CHOST} != ${CTARGET} ]]
+}
+
+just_headers() {
+	is_crosscompile && use headers-only
+}
+
+alt_prefix() {
+	is_crosscompile && echo /usr/${CTARGET}
+}
+
+# This prefix is applicable to CHOST when building against this
+# glibc. It is baked into the library at configure time.
+host_eprefix() {
+	is_crosscompile || echo "${EPREFIX}"
+}
+
+# This prefix is applicable to CBUILD when building against this
+# glibc. It determines the destination path at install time.
+build_eprefix() {
+	is_crosscompile && echo "${EPREFIX}"
+}
+
+# We need to be able to set alternative headers for compiling for non-native
+# platform. Will also become useful for testing kernel-headers without screwing
+# up the whole system.
+alt_headers() {
+	echo ${ALT_HEADERS:=$(alt_prefix)/usr/include}
+}
+
+alt_build_headers() {
+	if [[ -z ${ALT_BUILD_HEADERS} ]] ; then
+		ALT_BUILD_HEADERS="$(host_eprefix)$(alt_headers)"
+		if tc-is-cross-compiler ; then
+			ALT_BUILD_HEADERS=${SYSROOT}$(alt_headers)
+			if [[ ! -e ${ALT_BUILD_HEADERS}/linux/version.h ]] ; then
+				local header_path=$(echo '#include <linux/version.h>' | $(tc-getCPP ${CTARGET}) ${CFLAGS} 2>&1 | grep -o '[^"]*linux/version.h')
+				ALT_BUILD_HEADERS=${header_path%/linux/version.h}
+			fi
+		fi
+	fi
+	echo "${ALT_BUILD_HEADERS}"
+}
+
+alt_libdir() {
+	echo $(alt_prefix)/$(get_libdir)
+}
+alt_usrlibdir() {
+	echo $(alt_prefix)/usr/$(get_libdir)
+}
+
+builddir() {
+	echo "${WORKDIR}/build-${ABI}-${CTARGET}-$1"
+}
+
+do_compile_test() {
+	local ret save_cflags=${CFLAGS}
+	CFLAGS+=" $1"
+	shift
+
+	pushd "${T}" >/dev/null
+
+	rm -f glibc-test*
+	printf '%b' "$*" > glibc-test.c
+
+	nonfatal emake glibc-test
+	ret=$?
+
+	popd >/dev/null
+
+	CFLAGS=${save_cflags}
+	return ${ret}
+}
+
+do_run_test() {
+	local ret
+
+	if [[ ${MERGE_TYPE} == "binary" ]] ; then
+		# ignore build failures when installing a binary package #324685
+		do_compile_test "" "$@" 2>/dev/null || return 0
+	else
+		if ! do_compile_test "" "$@" ; then
+			ewarn "Simple build failed ... assuming this is desired #324685"
+			return 0
+		fi
+	fi
+
+	pushd "${T}" >/dev/null
+
+	./glibc-test
+	ret=$?
+	rm -f glibc-test*
+
+	popd >/dev/null
+
+	return ${ret}
+}
+
+setup_target_flags() {
+	# This largely mucks with compiler flags.  None of which should matter
+	# when building up just the headers.
+	just_headers && return 0
+
+	case $(tc-arch) in
+		x86)
+			# -march needed for #185404 #199334
+			# TODO: When creating the first glibc cross-compile, this test will
+			# always fail as it does a full link which in turn requires glibc.
+			# Probably also applies when changing multilib profile settings (e.g.
+			# enabling x86 when the profile was amd64-only previously).
+			# We could change main to _start and pass -nostdlib here so that we
+			# only test the gcc code compilation.  Or we could do a compile and
+			# then look for the symbol via scanelf.
+			if ! do_compile_test "" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+				local t=${CTARGET_OPT:-${CTARGET}}
+				t=${t%%-*}
+				filter-flags '-march=*'
+				export CFLAGS="-march=${t} ${CFLAGS}"
+				einfo "Auto adding -march=${t} to CFLAGS #185404"
+			fi
+		;;
+		amd64)
+			# -march needed for #185404 #199334
+			# TODO: See cross-compile issues listed above for x86.
+			[[ ${ABI} == x86 ]] &&
+			if ! do_compile_test "${CFLAGS_x86}" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+				local t=${CTARGET_OPT:-${CTARGET}}
+				t=${t%%-*}
+				# Normally the target is x86_64-xxx, so turn that into the -march that
+				# gcc actually accepts. #528708
+				[[ ${t} == "x86_64" ]] && t="x86-64"
+				filter-flags '-march=*'
+				# ugly, ugly, ugly.  ugly.
+				CFLAGS_x86=$(CFLAGS=${CFLAGS_x86} filter-flags '-march=*'; echo "${CFLAGS}")
+				export CFLAGS_x86="${CFLAGS_x86} -march=${t}"
+				einfo "Auto adding -march=${t} to CFLAGS_x86 #185404 (ABI=${ABI})"
+			fi
+		;;
+		mips)
+			# The mips abi cannot support the GNU style hashes. #233233
+			filter-ldflags -Wl,--hash-style=gnu -Wl,--hash-style=both
+		;;
+		sparc)
+			# Both sparc and sparc64 can use -fcall-used-g6.  -g7 is bad, though.
+			filter-flags "-fcall-used-g7"
+			append-flags "-fcall-used-g6"
+
+			# If the CHOST is the basic one (e.g. not sparcv9-xxx already),
+			# try to pick a better one so glibc can use cpu-specific .S files.
+			# We key off the CFLAGS to get a good value.  Also need to handle
+			# version skew.
+			# We can't force users to set their CHOST to their exact machine
+			# as many of these are not recognized by config.sub/gcc and such :(.
+			# Note: If the mcpu values don't scale, we might try probing CPP defines.
+			# Note: Should we factor in -Wa,-AvXXX flags too ?  Or -mvis/etc... ?
+
+			local cpu
+			case ${CTARGET} in
+			sparc64-*)
+				case $(get-flag mcpu) in
+				niagara[234])
+					if ver_test -ge 2.8 ; then
+						cpu="sparc64v2"
+					elif ver_test -ge 2.4 ; then
+						cpu="sparc64v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparc64b"
+					fi
+					;;
+				niagara)
+					if ver_test -ge 2.4 ; then
+						cpu="sparc64v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparc64b"
+					fi
+					;;
+				ultrasparc3)
+					cpu="sparc64b"
+					;;
+				*)
+					# We need to force at least v9a because the base build doesn't
+					# work with just v9.
+					# https://sourceware.org/bugzilla/show_bug.cgi?id=19477
+					[[ -z ${cpu} ]] && append-flags "-Wa,-xarch=v9a"
+					;;
+				esac
+				;;
+			sparc-*)
+				case $(get-flag mcpu) in
+				niagara[234])
+					if ver_test -ge 2.8 ; then
+						cpu="sparcv9v2"
+					elif ver_test -ge 2.4 ; then
+						cpu="sparcv9v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparcv9b"
+					else
+						cpu="sparcv9"
+					fi
+					;;
+				niagara)
+					if ver_test -ge 2.4 ; then
+						cpu="sparcv9v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparcv9b"
+					else
+						cpu="sparcv9"
+					fi
+					;;
+				ultrasparc3)
+					cpu="sparcv9b"
+					;;
+				v9|ultrasparc)
+					cpu="sparcv9"
+					;;
+				v8|supersparc|hypersparc|leon|leon3)
+					cpu="sparcv8"
+					;;
+				esac
+			;;
+			esac
+			[[ -n ${cpu} ]] && CTARGET_OPT="${cpu}-${CTARGET#*-}"
+		;;
+	esac
+}
+
+setup_flags() {
+	# Make sure host make.conf doesn't pollute us
+	if is_crosscompile || tc-is-cross-compiler ; then
+		CHOST=${CTARGET} strip-unsupported-flags
+	fi
+
+	# Store our CFLAGS because it's changed depending on which CTARGET
+	# we are building when pulling glibc on a multilib profile
+	CFLAGS_BASE=${CFLAGS_BASE-${CFLAGS}}
+	CFLAGS=${CFLAGS_BASE}
+	CXXFLAGS_BASE=${CXXFLAGS_BASE-${CXXFLAGS}}
+	CXXFLAGS=${CXXFLAGS_BASE}
+	ASFLAGS_BASE=${ASFLAGS_BASE-${ASFLAGS}}
+	ASFLAGS=${ASFLAGS_BASE}
+
+	# Allow users to explicitly avoid flag sanitization via
+	# USE=custom-cflags.
+	if ! use custom-cflags; then
+		# Over-zealous CFLAGS can often cause problems.  What may work for one
+		# person may not work for another.  To avoid a large influx of bugs
+		# relating to failed builds, we strip most CFLAGS out to ensure as few
+		# problems as possible.
+		strip-flags
+		# Lock glibc at -O2; we want to be conservative here.
+		filter-flags '-O?'
+		append-flags -O2
+	fi
+	strip-unsupported-flags
+	filter-flags -m32 -m64 '-mabi=*'
+
+	# glibc aborts if rpath is set by LDFLAGS
+	filter-ldflags '-Wl,-rpath=*'
+
+	# #492892
+	filter-flags -frecord-gcc-switches
+
+	unset CBUILD_OPT CTARGET_OPT
+	if use multilib ; then
+		CTARGET_OPT=$(get_abi_CTARGET)
+		[[ -z ${CTARGET_OPT} ]] && CTARGET_OPT=$(get_abi_CHOST)
+	fi
+
+	setup_target_flags
+
+	if [[ -n ${CTARGET_OPT} && ${CBUILD} == ${CHOST} ]] && ! is_crosscompile; then
+		CBUILD_OPT=${CTARGET_OPT}
+	fi
+
+	# glibc's headers disallow -O0 and fail at build time:
+	#  include/libc-symbols.h:75:3: #error "glibc cannot be compiled without optimization"
+	replace-flags -O0 -O1
+
+	filter-flags '-fstack-protector*'
+}
+
+want_tls() {
+	# Archs that can use TLS (Thread Local Storage)
+	case $(tc-arch) in
+		x86)
+			# requires i486 or better #106556
+			[[ ${CTARGET} == i[4567]86* ]] && return 0
+			return 1
+		;;
+	esac
+	return 0
+}
+
+want__thread() {
+	want_tls || return 1
+
+	# For some reason --with-tls --with__thread is causing segfaults on sparc32.
+	[[ ${PROFILE_ARCH} == "sparc" ]] && return 1
+
+	[[ -n ${WANT__THREAD} ]] && return ${WANT__THREAD}
+
+	# only test gcc -- can't test linking yet
+	tc-has-tls -c ${CTARGET}
+	WANT__THREAD=$?
+
+	return ${WANT__THREAD}
+}
+
+use_multiarch() {
+	# Allow user to disable runtime arch detection in multilib.
+	use multiarch || return 1
+	# Make sure binutils is new enough to support indirect functions,
+	# #336792. This funky sed supports gold and bfd linkers.
+	local bver nver
+	bver=$($(tc-getLD ${CTARGET}) -v | sed -n -r '1{s:[^0-9]*::;s:^([0-9.]*).*:\1:;p}')
+	case $(tc-arch ${CTARGET}) in
+	amd64|x86) nver="2.20" ;;
+	arm)       nver="2.22" ;;
+	hppa)      nver="2.23" ;;
+	ppc|ppc64) nver="2.20" ;;
+	# ifunc support was added in 2.23, but glibc also needs
+	# machinemode which is in 2.24.
+	s390)      nver="2.24" ;;
+	sparc)     nver="2.21" ;;
+	*)         return 1 ;;
+	esac
+	ver_test ${bver} -ge ${nver}
+}
+
+# Setup toolchain variables that had historically been defined in the
+# profiles for these archs.
+setup_env() {
+	# silly users
+	unset LD_RUN_PATH
+	unset LD_ASSUME_KERNEL
+
+	if is_crosscompile || tc-is-cross-compiler ; then
+		multilib_env ${CTARGET_OPT:-${CTARGET}}
+
+		if ! use multilib ; then
+			MULTILIB_ABIS=${DEFAULT_ABI}
+		else
+			MULTILIB_ABIS=${MULTILIB_ABIS:-${DEFAULT_ABI}}
+		fi
+
+		# If the user has CFLAGS_<CTARGET> in their make.conf, use that,
+		# and fall back on CFLAGS.
+		local VAR=CFLAGS_${CTARGET//[-.]/_}
+		CFLAGS=${!VAR-${CFLAGS}}
+		einfo " $(printf '%15s' 'Manual CFLAGS:')   ${CFLAGS}"
+	fi
+
+	setup_flags
+
+	export ABI=${ABI:-${DEFAULT_ABI:-default}}
+
+	if just_headers ; then
+		# Avoid mixing host's CC and target's CFLAGS_${ABI}:
+		# At this bootstrap stage we have only binutils for
+		# target but not compiler yet.
+		einfo "Skip CC ABI injection. We can't use (cross-)compiler yet."
+		return 0
+	fi
+	local VAR=CFLAGS_${ABI}
+	# We need to export CFLAGS with abi information in them because glibc's
+	# configure script checks CFLAGS for some targets (like mips).  Keep
+	# around the original clean value to avoid appending multiple ABIs on
+	# top of each other.
+	: ${__GLIBC_CC:=$(tc-getCC ${CTARGET_OPT:-${CTARGET}})}
+	export __GLIBC_CC CC="${__GLIBC_CC} ${!VAR}"
+	einfo " $(printf '%15s' 'Manual CC:')   ${CC}"
+}
+
+foreach_abi() {
+	setup_env
+
+	local ret=0
+	local abilist=""
+	if use multilib ; then
+		abilist=$(get_install_abis)
+	else
+		abilist=${DEFAULT_ABI}
+	fi
+	local -x ABI
+	for ABI in ${abilist:-default} ; do
+		setup_env
+		einfo "Running $1 for ABI ${ABI}"
+		$1
+		: $(( ret |= $? ))
+	done
+	return ${ret}
+}
+
+glibc_banner() {
+	local b="Gentoo ${PVR}"
+	[[ -n ${PATCH_VER} ]] && ! use vanilla && b+=" p${PATCH_VER}"
+	echo "${b}"
+}
+
+check_devpts() {
+	# Make sure devpts is mounted correctly for use w/out setuid pt_chown.
+
+	# If merely building the binary package, then there's nothing to verify.
+	[[ ${MERGE_TYPE} == "buildonly" ]] && return
+
+	# Only sanity check when installing the native glibc.
+	[[ -n ${ROOT} ]] && return
+
+	# If they're opting in to the old suid code, then no need to check.
+	use suid && return
+
+	if awk '$3 == "devpts" && $4 ~ /[, ]gid=5[, ]/ { exit 1 }' /proc/mounts ; then
+		eerror "In order to use glibc with USE=-suid, you must make sure that"
+		eerror "you have devpts mounted at /dev/pts with the gid=5 option."
+		eerror "Openrc should do this for you, so you should check /etc/fstab"
+		eerror "and make sure you do not have any invalid settings there."
+		die "mount & fix your /dev/pts settings"
+	fi
+}
+
+# The following Kernel version handling functions are mostly copied from portage
+# source. It's better not to use linux-info.eclass here since a) it adds too
+# much magic, see bug 326693 for some of the arguments, and b) some of the
+# functions are just not provided.
+
+g_get_running_KV() {
+	uname -r
+	return $?
+}
+
+g_KV_major() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	echo "${KV%%.*}"
+}
+
+g_KV_minor() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.}
+	echo "${KV%%.*}"
+}
+
+g_KV_micro() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.*.}
+	echo "${KV%%[^[:digit:]]*}"
+}
+
+g_KV_to_int() {
+	[[ -z $1 ]] && return 1
+	local KV_MAJOR=$(g_KV_major "$1")
+	local KV_MINOR=$(g_KV_minor "$1")
+	local KV_MICRO=$(g_KV_micro "$1")
+	local KV_int=$(( KV_MAJOR * 65536 + KV_MINOR * 256 + KV_MICRO ))
+
+	# We make version 2.2.0 the minimum version we will handle as
+	# a sanity check ... if its less, we fail ...
+	if [[ ${KV_int} -ge 131584 ]] ; then
+		echo "${KV_int}"
+		return 0
+	fi
+	return 1
+}
+
+g_int_to_KV() {
+	local version=$1 major minor micro
+	major=$((version / 65536))
+	minor=$(((version % 65536) / 256))
+	micro=$((version % 256))
+	echo ${major}.${minor}.${micro}
+}
+
+eend_KV() {
+	[[ $(g_KV_to_int $1) -ge $(g_KV_to_int $2) ]]
+	eend $?
+}
+
+get_kheader_version() {
+	printf '#include <linux/version.h>\nLINUX_VERSION_CODE\n' | \
+	$(tc-getCPP ${CTARGET}) -I "$(build_eprefix)$(alt_build_headers)" - | \
+	tail -n 1
+}
+
+# We collect all sanity checks here. Consistency is not guranteed between
+# pkg_ and src_ phases, so we call this function both in pkg_pretend and in
+# src_unpack.
+sanity_prechecks() {
+	# Make sure devpts is mounted correctly for use w/out setuid pt_chown
+	check_devpts
+
+	# Prevent native builds from downgrading
+	if [[ ${MERGE_TYPE} != "buildonly" ]] && \
+	   [[ -z ${ROOT} ]] && \
+	   [[ ${CBUILD} == ${CHOST} ]] && \
+	   [[ ${CHOST} == ${CTARGET} ]] ; then
+
+		# The high rev # is to allow people to downgrade between -r#
+		# versions. We want to block 2.20->2.19, but 2.20-r3->2.20-r2
+		# should be fine. Hopefully we never actually use a r# this
+		# high.
+		if has_version ">${CATEGORY}/${P}-r10000" ; then
+			eerror "Sanity check to keep you from breaking your system:"
+			eerror " Downgrading glibc is not supported and a sure way to destruction."
+			[[ ${I_ALLOW_TO_BREAK_MY_SYSTEM} = yes ]] || die "Aborting to save your system."
+		fi
+
+		if ! do_run_test '#include <unistd.h>\n#include <sys/syscall.h>\nint main(){return syscall(1000)!=-1;}\n' ; then
+			eerror "Your old kernel is broken. You need to update it to a newer"
+			eerror "version as syscall(<bignum>) will break. See bug 279260."
+			die "Old and broken kernel."
+		fi
+	fi
+
+	# Users have had a chance to phase themselves, time to give em the boot
+	if [[ -e ${EROOT}/etc/locale.gen ]] && [[ -e ${EROOT}/etc/locales.build ]] ; then
+		eerror "You still haven't deleted ${EROOT}/etc/locales.build."
+		eerror "Do so now after making sure ${EROOT}/etc/locale.gen is kosher."
+		die "Lazy upgrader detected"
+	fi
+
+	if [[ ${CTARGET} == i386-* ]] ; then
+		eerror "i386 CHOSTs are no longer supported."
+		eerror "Chances are you don't actually want/need i386."
+		eerror "Please read https://www.gentoo.org/doc/en/change-chost.xml"
+		die "Please fix your CHOST"
+	fi
+
+	if [[ -e /proc/xen ]] && [[ $(tc-arch) == "x86" ]] && ! is-flag -mno-tls-direct-seg-refs ; then
+		ewarn "You are using Xen but don't have -mno-tls-direct-seg-refs in your CFLAGS."
+		ewarn "This will result in a 50% performance penalty when running with a 32bit"
+		ewarn "hypervisor, which is probably not what you want."
+	fi
+
+	# Check for sanity of /etc/nsswitch.conf
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] ; then
+		local entry
+		for entry in passwd group shadow; do
+			if ! egrep -q "^[ \t]*${entry}:.*files" "${EROOT}"/etc/nsswitch.conf; then
+				eerror "Your ${EROOT}/etc/nsswitch.conf is out of date."
+				eerror "Please make sure you have 'files' entries for"
+				eerror "'passwd:', 'group:' and 'shadow:' databases."
+				eerror "For more details see:"
+				eerror "  https://wiki.gentoo.org/wiki/Project:Toolchain/nsswitch.conf_in_glibc-2.26"
+				die "nsswitch.conf has no 'files' provider in '${entry}'."
+			fi
+		done
+	fi
+
+	# ABI-specific checks follow here. Hey, we have a lot more specific conditions that
+	# we test for...
+	if ! is_crosscompile ; then
+		if use amd64 && use multilib && [[ ${MERGE_TYPE} != "binary" ]] ; then
+			ebegin "Checking that IA32 emulation is enabled in the running kernel"
+			echo 'int main(){return 0;}' > "${T}/check-ia32-emulation.c"
+			local STAT
+			if "${CC-${CHOST}-gcc}" ${CFLAGS_x86} "${T}/check-ia32-emulation.c" -o "${T}/check-ia32-emulation.elf32"; then
+				"${T}/check-ia32-emulation.elf32"
+				STAT=$?
+			else
+				# Don't fail here to allow single->multi ABI switch
+				# or recover from breakage like bug #646424
+				ewarn "Failed to compile the ABI test. Broken host glibc?"
+				STAT=0
+			fi
+			rm -f "${T}/check-ia32-emulation.elf32"
+			eend $STAT
+			[[ $STAT -eq 0 ]] || die "CONFIG_IA32_EMULATION must be enabled in the kernel to compile a multilib glibc."
+		fi
+
+	fi
+
+	# When we actually have to compile something...
+	if ! just_headers ; then
+		ebegin "Checking gcc for __thread support"
+		if ! eend $(want__thread ; echo $?) ; then
+			echo
+			eerror "Could not find a gcc that supports the __thread directive!"
+			eerror "Please update your binutils/gcc and try again."
+			die "No __thread support in gcc!"
+		fi
+
+		if [[ ${CTARGET} == *-linux* ]] ; then
+			local run_kv build_kv want_kv
+
+			run_kv=$(g_get_running_KV)
+			build_kv=$(g_int_to_KV $(get_kheader_version))
+			want_kv=${MIN_KERN_VER}
+
+			if ! is_crosscompile && ! tc-is-cross-compiler ; then
+				# Building fails on an non-supporting kernel
+				ebegin "Checking running kernel version (${run_kv} >= ${want_kv})"
+				if ! eend_KV ${run_kv} ${want_kv} ; then
+					echo
+					eerror "You need a kernel of at least ${want_kv}!"
+					die "Kernel version too low!"
+				fi
+			fi
+
+			ebegin "Checking linux-headers version (${build_kv} >= ${want_kv})"
+			if ! eend_KV ${build_kv} ${want_kv} ; then
+				echo
+				eerror "You need linux-headers of at least ${want_kv}!"
+				die "linux-headers version too low!"
+			fi
+		fi
+	fi
+}
+
+#
+# the phases
+#
+
+# pkg_pretend
+
+pkg_pretend() {
+	# All the checks...
+	einfo "Checking general environment sanity."
+	sanity_prechecks
+}
+
+pkg_setup() {
+	# see bug 682570
+	[[ -z ${BOOTSTRAP_RAP} ]] && python-any-r1_pkg_setup
+}
+
+# src_unpack
+
+src_unpack() {
+	# Consistency is not guaranteed between pkg_ and src_ ...
+	sanity_prechecks
+
+	use multilib && unpack gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz
+
+	setup_env
+
+	if [[ -n ${EGIT_REPO_URI} ]] ; then
+		git-r3_src_unpack
+	else
+		unpack ${P}.tar.xz
+	fi
+
+	cd "${WORKDIR}" || die
+	unpack glibc-${RELEASE_VER}-patches-${PATCH_VER}.tar.xz
+}
+
+src_prepare() {
+	if ! use vanilla ; then
+		elog "Applying Gentoo Glibc Patchset ${RELEASE_VER}-${PATCH_VER}"
+		eapply "${WORKDIR}"/patches
+		einfo "Done."
+	fi
+
+	default
+
+	gnuconfig_update
+
+	cd "${WORKDIR}"
+	find . -name configure -exec touch {} +
+
+	eprefixify extra/locale/locale-gen
+
+	# Fix permissions on some of the scripts.
+	chmod u+x "${S}"/scripts/*.sh
+
+	cd "${S}"
+}
+
+glibc_do_configure() {
+	# Glibc does not work with gold (for various reasons) #269274.
+	tc-ld-disable-gold
+
+	# CXX isnt handled by the multilib system, so if we dont unset here
+	# we accumulate crap across abis
+	unset CXX
+
+	einfo "Configuring glibc for nptl"
+
+	if use doc ; then
+		export MAKEINFO=makeinfo
+	else
+		export MAKEINFO=/dev/null
+	fi
+
+	local v
+	for v in ABI CBUILD CHOST CTARGET CBUILD_OPT CTARGET_OPT CC CXX LD {AS,C,CPP,CXX,LD}FLAGS MAKEINFO ; do
+		einfo " $(printf '%15s' ${v}:)   ${!v}"
+	done
+
+	# CFLAGS can contain ABI-specific flags like -mfpu=neon, see bug #657760
+	# To build .S (assembly) files with the same ABI-specific flags
+	# upstream currently recommends adding CFLAGS to CC/CXX:
+	#    https://sourceware.org/PR23273
+	# Note: Passing CFLAGS via CPPFLAGS overrides glibc's arch-specific CFLAGS
+	# and breaks multiarch support. See 659030#c3 for an example.
+	# The glibc configure script doesn't properly use LDFLAGS all the time.
+	export CC="$(tc-getCC ${CTARGET}) ${CFLAGS} ${LDFLAGS}"
+	einfo " $(printf '%15s' 'Manual CC:')   ${CC}"
+
+	# Some of the tests are written in C++, so we need to force our multlib abis in, bug 623548
+	export CXX="$(tc-getCXX ${CTARGET}) $(get_abi_CFLAGS) ${CFLAGS}"
+
+	if is_crosscompile; then
+		# Assume worst-case bootstrap: glibc is buil first time
+		# when ${CTARGET}-g++ is not available yet. We avoid
+		# building auxiliary programs that require C++: bug #683074
+		# It should not affect final result.
+		export libc_cv_cxx_link_ok=no
+		# The line above has the same effect. We set CXX explicitly
+		# to make build logs less confusing.
+		export CXX=
+	fi
+	einfo " $(printf '%15s' 'Manual CXX:')   ${CXX}"
+
+	echo
+
+	local myconf=()
+
+	case ${CTARGET} in
+		m68k*)
+			# setjmp() is not compatible with stack protection:
+			# https://sourceware.org/PR24202
+			myconf+=( --enable-stack-protector=no )
+			;;
+		powerpc-*)
+			# Currently gcc on powerpc32 generates invalid code for
+			# __builtin_return_address(0) calls. Normally programs
+			# don't do that but malloc hooks in glibc do:
+			# https://gcc.gnu.org/PR81996
+			# https://bugs.gentoo.org/629054
+			myconf+=( --enable-stack-protector=no )
+			;;
+		*)
+			myconf+=( --enable-stack-protector=$(usex ssp all no) )
+			;;
+	esac
+	myconf+=( --enable-stackguard-randomization )
+
+	# Keep a whitelist of targets supporing IFUNC. glibc's ./configure
+	# is not robust enough to detect proper support:
+	#    https://bugs.gentoo.org/641216
+	#    https://sourceware.org/PR22634#c0
+	case $(tc-arch ${CTARGET}) in
+		# Keep whitelist of targets where autodetection mostly works.
+		amd64|x86|sparc|ppc|ppc64|arm|arm64|s390) ;;
+		# Blacklist everywhere else
+		*) myconf+=( libc_cv_ld_gnu_indirect_function=no ) ;;
+	esac
+
+	# Enable Intel Control-flow Enforcement Technology on amd64 if requested
+	case ${CTARGET} in
+		x86_64-*) myconf+=( $(use_enable cet) ) ;;
+		*) ;;
+	esac
+
+	[[ $(tc-is-softfloat) == "yes" ]] && myconf+=( --without-fp )
+
+	myconf+=( --enable-kernel=${MIN_KERN_VER} )
+
+	# Since SELinux support is only required for nscd, only enable it if:
+	# 1. USE selinux
+	# 2. only for the primary ABI on multilib systems
+	# 3. Not a crosscompile
+	if ! is_crosscompile && use selinux ; then
+		if use multilib ; then
+			if is_final_abi ; then
+				myconf+=( --with-selinux )
+			else
+				myconf+=( --without-selinux )
+			fi
+		else
+			myconf+=( --with-selinux )
+		fi
+	else
+		myconf+=( --without-selinux )
+	fi
+
+	# Force a few tests where we always know the answer but
+	# configure is incapable of finding it.
+	if is_crosscompile ; then
+		export \
+			libc_cv_c_cleanup=yes \
+			libc_cv_forced_unwind=yes
+	fi
+
+	myconf+=(
+		--without-cvs
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		$(use_enable profile)
+		$(use_with gd)
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		--sysconfdir="$(host_eprefix)/etc"
+		--localstatedir="$(host_eprefix)/var"
+		--libdir='$(prefix)'/$(get_libdir)
+		--mandir='$(prefix)'/share/man
+		--infodir='$(prefix)'/share/info
+		--libexecdir='$(libdir)'/misc/glibc
+		--with-bugurl=https://bugs.gentoo.org/
+		--with-pkgversion="$(glibc_banner)"
+		$(use_enable crypt)
+		$(use_multiarch || echo --disable-multi-arch)
+		$(use_enable systemtap)
+		$(use_enable nscd)
+		${EXTRA_ECONF}
+	)
+
+	# We rely on sys-libs/timezone-data for timezone tools normally.
+	myconf+=( $(use_enable vanilla timezone-tools) )
+
+	# These libs don't have configure flags.
+	ac_cv_lib_audit_audit_log_user_avc_message=$(usex audit || echo no)
+	ac_cv_lib_cap_cap_init=$(usex caps || echo no)
+
+	# There is no configure option for this and we need to export it
+	# since the glibc build will re-run configure on itself
+	export libc_cv_rootsbindir="$(host_eprefix)/sbin"
+	export libc_cv_slibdir="$(host_eprefix)/$(get_libdir)"
+
+	# We take care of patching our binutils to use both hash styles,
+	# and many people like to force gnu hash style only, so disable
+	# this overriding check.  #347761
+	export libc_cv_hashstyle=no
+
+	local builddir=$(builddir nptl)
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+	set -- "${S}"/configure "${myconf[@]}"
+	echo "$@"
+	"$@" || die "failed to configure glibc"
+
+	# ia64 static cross-compilers are a pita in so much that they
+	# can't produce static ELFs (as the libgcc.a is broken).  so
+	# disable building of the programs for those targets if it
+	# doesn't work.
+	# XXX: We could turn this into a compiler test, but ia64 is
+	# the only one that matters, so this should be fine for now.
+	if is_crosscompile && [[ ${CTARGET} == ia64* ]] ; then
+		sed -i '1i+link-static = touch $@' config.make
+	fi
+
+	# If we're trying to migrate between ABI sets, we need
+	# to lie and use a local copy of gcc.  Like if the system
+	# is built with MULTILIB_ABIS="amd64 x86" but we want to
+	# add x32 to it, gcc/glibc don't yet support x32.
+	#
+	if [[ -n ${GCC_BOOTSTRAP_VER} ]] && use multilib ; then
+		echo 'main(){}' > "${T}"/test.c
+		if ! $(tc-getCC ${CTARGET}) ${CFLAGS} ${LDFLAGS} "${T}"/test.c -Wl,-emain -lgcc 2>/dev/null ; then
+			sed -i -e '/^CC = /s:$: -B$(objdir)/../'"gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}/${ABI}:" config.make || die
+		fi
+	fi
+}
+
+glibc_headers_configure() {
+	export ABI=default
+
+	local builddir=$(builddir "headers")
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+
+	# if we don't have a compiler yet, we can't really test it now ...
+	# hopefully they don't affect header generation, so let's hope for
+	# the best here ...
+	local v vars=(
+		ac_cv_header_cpuid_h=yes
+		libc_cv_{386,390,alpha,arm,hppa,ia64,mips,{powerpc,sparc}{,32,64},sh,x86_64}_tls=yes
+		libc_cv_asm_cfi_directives=yes
+		libc_cv_broken_visibility_attribute=no
+		libc_cv_c_cleanup=yes
+		libc_cv_compiler_powerpc64le_binary128_ok=yes
+		libc_cv_forced_unwind=yes
+		libc_cv_gcc___thread=yes
+		libc_cv_mlong_double_128=yes
+		libc_cv_mlong_double_128ibm=yes
+		libc_cv_ppc_machine=yes
+		libc_cv_ppc_rel16=yes
+		libc_cv_predef_fortify_source=no
+		libc_cv_target_power8_ok=yes
+		libc_cv_visibility_attribute=yes
+		libc_cv_z_combreloc=yes
+		libc_cv_z_execstack=yes
+		libc_cv_z_initfirst=yes
+		libc_cv_z_nodelete=yes
+		libc_cv_z_nodlopen=yes
+		libc_cv_z_relro=yes
+		libc_mips_abi=${ABI}
+		libc_mips_float=$([[ $(tc-is-softfloat) == "yes" ]] && echo soft || echo hard)
+		# These libs don't have configure flags.
+		ac_cv_lib_audit_audit_log_user_avc_message=no
+		ac_cv_lib_cap_cap_init=no
+	)
+
+	einfo "Forcing cached settings:"
+	for v in "${vars[@]}" ; do
+		einfo " ${v}"
+		export ${v}
+	done
+
+	local headers_only_arch_CPPFLAGS=()
+
+	# Blow away some random CC settings that screw things up. #550192
+	if [[ -d ${S}/sysdeps/mips ]]; then
+		pushd "${S}"/sysdeps/mips >/dev/null
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=32:' mips32/Makefile mips64/n32/Makefile || die
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=64:' mips64/n64/Makefile || die
+
+		# Force the mips ABI to the default.  This is OK because the set of
+		# installed headers in this phase is the same between the 3 ABIs.
+		# If this ever changes, this hack will break, but that's unlikely
+		# as glibc discourages that behavior.
+		# https://crbug.com/647033
+		sed -i -e 's:abiflag=.*:abiflag=_ABIO32:' preconfigure || die
+
+		popd >/dev/null
+	fi
+
+	case ${CTARGET} in
+	riscv*)
+		# RISC-V interrogates the compiler to determine which target to
+		# build.  If building the headers then we don't strictly need a
+		# RISC-V compiler, so the built-in definitions that are provided
+		# along with all RISC-V compiler might not exist.  This causes
+		# glibc's RISC-V preconfigure script to blow up.  Since we're just
+		# building the headers any value will actually work here, so just
+		# pick the standard one (rv64g/lp64d) to make the build scripts
+		# happy for now -- the headers are all the same anyway so it
+		# doesn't matter.
+		headers_only_arch_CPPFLAGS+=(
+			-D__riscv_xlen=64
+			-D__riscv_flen=64
+			-D__riscv_float_abi_double=1
+			-D__riscv_atomic=1
+		) ;;
+	esac
+
+	local myconf=()
+	myconf+=(
+		--disable-sanity-checks
+		--enable-hacker-mode
+		--without-cvs
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		${EXTRA_ECONF}
+	)
+
+	# Nothing is compiled here which would affect the headers for the target.
+	# So forcing CC/CFLAGS is sane.
+	local headers_only_CC=$(tc-getBUILD_CC)
+	local headers_only_CFLAGS="-O1 -pipe"
+	local headers_only_CPPFLAGS="-U_FORTIFY_SOURCE ${headers_only_arch_CPPFLAGS[*]}"
+	local headers_only_LDFLAGS=""
+	set -- "${S}"/configure "${myconf[@]}"
+	echo \
+		"CC=${headers_only_CC}" \
+		"CFLAGS=${headers_only_CFLAGS}" \
+		"CPPFLAGS=${headers_only_CPPFLAGS}" \
+		"LDFLAGS=${headers_only_LDFLAGS}" \
+		"$@"
+	CC=${headers_only_CC} \
+	CFLAGS=${headers_only_CFLAGS} \
+	CPPFLAGS=${headers_only_CPPFLAGS} \
+	LDFLAGS="" \
+	"$@" || die "failed to configure glibc"
+}
+
+do_src_configure() {
+	if just_headers ; then
+		glibc_headers_configure
+	else
+		glibc_do_configure nptl
+	fi
+}
+
+src_configure() {
+	foreach_abi do_src_configure
+}
+
+do_src_compile() {
+	emake -C "$(builddir nptl)"
+}
+
+src_compile() {
+	if just_headers ; then
+		return
+	fi
+
+	foreach_abi do_src_compile
+}
+
+glibc_src_test() {
+	cd "$(builddir nptl)"
+	emake check
+}
+
+do_src_test() {
+	local ret=0
+
+	glibc_src_test
+	: $(( ret |= $? ))
+
+	return ${ret}
+}
+
+src_test() {
+	if just_headers ; then
+		return
+	fi
+
+	# Give tests more time to complete.
+	export TIMEOUTFACTOR=5
+
+	foreach_abi do_src_test || die "tests failed"
+}
+
+run_locale_gen() {
+	# if the host locales.gen contains no entries, we'll install everything
+	local root="$1"
+	local inplace=""
+
+	if [[ "${root}" == "--inplace-glibc" ]] ; then
+		inplace="--inplace-glibc"
+		root="$2"
+	fi
+
+	local locale_list="${root}/etc/locale.gen"
+
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	if [[ -z $(locale-gen --list --config "${locale_list}") ]] ; then
+		[[ -z ${inplace} ]] && ewarn "Generating all locales; edit /etc/locale.gen to save time/space"
+		locale_list="${root}/usr/share/i18n/SUPPORTED"
+	fi
+
+	locale-gen ${inplace} --jobs $(makeopts_jobs) --config "${locale_list}" \
+		--destdir "${root}"
+
+	popd >/dev/null
+}
+
+glibc_do_src_install() {
+	local builddir=$(builddir nptl)
+	cd "${builddir}"
+
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install
+
+	# This version (2.26) provides some compatibility libraries for the NIS/NIS+ support
+	# which come without headers etc. Only needed for binary packages since the
+	# external net-libs/libnsl has increased soversion. Keep only versioned libraries.
+	find "${D}" -name "libnsl.a" -delete
+	find "${D}" -name "libnsl.so" -delete
+
+	# Normally upstream_pv is ${PV}. Live ebuilds are exception, there we need
+	# to infer upstream version:
+	# '#define VERSION "2.26.90"' -> '2.26.90'
+	local upstream_pv=$(sed -n -r 's/#define VERSION "(.*)"/\1/p' "${S}"/version.h)
+
+	# Avoid stripping binaries not targeted by ${CHOST}. Or else
+	# ${CHOST}-strip would break binaries build for ${CTARGET}.
+	is_crosscompile && dostrip -x /
+	# gdb thread introspection relies on local libpthreas symbols. stripping breaks it
+	# See Note [Disable automatic stripping]
+	dostrip -x $(alt_libdir)/libpthread-${upstream_pv}.so
+
+	if [[ -e ${ED}/$(alt_usrlibdir)/libm-${upstream_pv}.a ]] ; then
+		# Move versioned .a file out of libdir to evade portage QA checks
+		# instead of using gen_usr_ldscript(). We fix ldscript as:
+		# "GROUP ( /usr/lib64/libm-<pv>.a ..." -> "GROUP ( /usr/lib64/glibc-<pv>/libm-<pv>.a ..."
+		sed -i "s@\(libm-${upstream_pv}.a\)@${P}/\1@" "${ED}"/$(alt_usrlibdir)/libm.a || die
+		dodir $(alt_usrlibdir)/${P}
+		mv "${ED}"/$(alt_usrlibdir)/libm-${upstream_pv}.a "${ED}"/$(alt_usrlibdir)/${P}/libm-${upstream_pv}.a || die
+	fi
+
+	# We'll take care of the cache ourselves
+	rm -f "${ED}"/etc/ld.so.cache
+
+	# Everything past this point just needs to be done once ...
+	is_final_abi || return 0
+
+	# Make sure the non-native interp can be found on multilib systems even
+	# if the main library set isn't installed into the right place.  Maybe
+	# we should query the active gcc for info instead of hardcoding it ?
+	local i ldso_abi ldso_name
+	local ldso_abi_list=(
+		# x86
+		amd64   /lib64/ld-linux-x86-64.so.2
+		x32     /libx32/ld-linux-x32.so.2
+		x86     /lib/ld-linux.so.2
+		# mips
+		o32     /lib/ld.so.1
+		n32     /lib32/ld.so.1
+		n64     /lib64/ld.so.1
+		# powerpc
+		ppc     /lib/ld.so.1
+		ppc64   /lib64/ld64.so.1
+		# riscv
+		lp64d   /lib/ld-linux-riscv64-lp64d.so.1
+		lp64    /lib/ld-linux-riscv64-lp64.so.1
+		# s390
+		s390    /lib/ld.so.1
+		s390x   /lib/ld64.so.1
+		# sparc
+		sparc32 /lib/ld-linux.so.2
+		sparc64 /lib64/ld-linux.so.2
+	)
+	case $(tc-endian) in
+	little)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64.so.1
+		)
+		;;
+	big)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64_be.so.1
+		)
+		;;
+	esac
+	if [[ ${SYMLINK_LIB} == "yes" ]] && [[ ! -e ${ED}/$(alt_prefix)/lib ]] ; then
+		dosym $(get_abi_LIBDIR ${DEFAULT_ABI}) $(alt_prefix)/lib
+	fi
+	for (( i = 0; i < ${#ldso_abi_list[@]}; i += 2 )) ; do
+		ldso_abi=${ldso_abi_list[i]}
+		has ${ldso_abi} $(get_install_abis) || continue
+
+		ldso_name="$(alt_prefix)${ldso_abi_list[i+1]}"
+		if [[ ! -L ${ED}/${ldso_name} && ! -e ${ED}/${ldso_name} ]] ; then
+			dosym ../$(get_abi_LIBDIR ${ldso_abi})/${ldso_name##*/} ${ldso_name}
+		fi
+	done
+
+	# With devpts under Linux mounted properly, we do not need the pt_chown
+	# binary to be setuid.  This is because the default owners/perms will be
+	# exactly what we want.
+	if ! use suid ; then
+		find "${ED}" -name pt_chown -exec chmod -s {} +
+	fi
+
+	#################################################################
+	# EVERYTHING AFTER THIS POINT IS FOR NATIVE GLIBC INSTALLS ONLY #
+	# Make sure we install some symlink hacks so that when we build
+	# a 2nd stage cross-compiler, gcc finds the target system
+	# headers correctly.  See gcc/doc/gccinstall.info
+	if is_crosscompile ; then
+		# We need to make sure that /lib and /usr/lib always exists.
+		# gcc likes to use relative paths to get to its multilibs like
+		# /usr/lib/../lib64/.  So while we don't install any files into
+		# /usr/lib/, we do need it to exist.
+		keepdir $(alt_prefix)/lib
+		keepdir $(alt_prefix)/usr/lib
+
+		dosym usr/include $(alt_prefix)/sys-include
+		return 0
+	fi
+
+	# Files for Debian-style locale updating
+	dodir /usr/share/i18n
+	sed \
+		-e "/^#/d" \
+		-e "/SUPPORTED-LOCALES=/d" \
+		-e "s: \\\\::g" -e "s:/: :g" \
+		"${S}"/localedata/SUPPORTED > "${ED}"/usr/share/i18n/SUPPORTED \
+		|| die "generating /usr/share/i18n/SUPPORTED failed"
+	cd "${WORKDIR}"/extra/locale
+	dosbin locale-gen
+	doman *.[0-8]
+	insinto /etc
+	doins locale.gen
+
+	# Make sure all the ABI's can find the locales and so we only
+	# have to generate one set
+	local a
+	keepdir /usr/$(get_libdir)/locale
+	for a in $(get_install_abis) ; do
+		if [[ ! -e ${ED}/usr/$(get_abi_LIBDIR ${a})/locale ]] ; then
+			dosym ../$(get_libdir)/locale /usr/$(get_abi_LIBDIR ${a})/locale
+		fi
+	done
+
+	# HACK: If we're building for riscv, we need to additionally make sure that
+	# we can find the locale archive afterwards
+	case ${CTARGET} in
+		riscv*)
+			if [[ ! -e ${ED}/usr/lib/locale ]] ; then
+				dosym ../$(get_libdir)/locale /usr/lib/locale
+			fi
+			;;
+		*) ;;
+	esac
+
+	cd "${S}"
+
+	# Install misc network config files
+	insinto /etc
+	doins nscd/nscd.conf posix/gai.conf nss/nsswitch.conf
+	doins "${WORKDIR}"/extra/etc/*.conf
+
+	if use nscd ; then
+		doinitd "$(prefixify_ro "${WORKDIR}"/extra/etc/nscd)"
+
+		local nscd_args=(
+			-e "s:@PIDFILE@:$(strings "${ED}"/usr/sbin/nscd | grep nscd.pid):"
+		)
+
+		sed -i "${nscd_args[@]}" "${ED}"/etc/init.d/nscd
+
+		systemd_dounit nscd/nscd.service
+		systemd_newtmpfilesd nscd/nscd.tmpfiles nscd.conf
+	else
+		# Do this since extra/etc/*.conf above might have nscd.conf.
+		rm -f "${ED}"/etc/nscd.conf
+	fi
+
+	echo 'LDPATH="include ld.so.conf.d/*.conf"' > "${T}"/00glibc
+	doenvd "${T}"/00glibc
+
+	for d in BUGS ChangeLog CONFORMANCE FAQ NEWS NOTES PROJECTS README* ; do
+		[[ -s ${d} ]] && dodoc ${d}
+	done
+	dodoc -r ChangeLog.old
+
+	# Prevent overwriting of the /etc/localtime symlink.  We'll handle the
+	# creation of the "factory" symlink in pkg_postinst().
+	rm -f "${ED}"/etc/localtime
+
+	# Generate all locales if this is a native build as locale generation
+	if use compile-locales && ! is_crosscompile ; then
+		run_locale_gen --inplace-glibc "${ED}/"
+		sed -e 's:COMPILED_LOCALES="":COMPILED_LOCALES="1":' -i "${ED}"/usr/sbin/locale-gen || die
+	fi
+}
+
+glibc_headers_install() {
+	local builddir=$(builddir "headers")
+	cd "${builddir}"
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install-headers
+
+	insinto $(alt_headers)/gnu
+	doins "${S}"/include/gnu/stubs.h
+
+	# Make sure we install the sys-include symlink so that when
+	# we build a 2nd stage cross-compiler, gcc finds the target
+	# system headers correctly.  See gcc/doc/gccinstall.info
+	dosym usr/include $(alt_prefix)/sys-include
+}
+
+src_install() {
+	if just_headers ; then
+		export ABI=default
+		glibc_headers_install
+		return
+	fi
+
+	foreach_abi glibc_do_src_install
+
+	if ! use static-libs ; then
+		elog "Not installing static glibc libraries"
+		find "${ED}" -name "*.a" -and -not -name "*_nonshared.a" -delete
+	fi
+}
+
+# Simple test to make sure our new glibc isn't completely broken.
+# Make sure we don't test with statically built binaries since
+# they will fail.  Also, skip if this glibc is a cross compiler.
+#
+# If coreutils is built with USE=multicall, some of these files
+# will just be wrapper scripts, not actual ELFs we can test.
+glibc_sanity_check() {
+	cd / #228809
+
+	# We enter ${ED} so to avoid trouble if the path contains
+	# special characters; for instance if the path contains the
+	# colon character (:), then the linker will try to split it
+	# and look for the libraries in an unexpected place. This can
+	# lead to unsafe code execution if the generated prefix is
+	# within a world-writable directory.
+	# (e.g. /var/tmp/portage:${HOSTNAME})
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	local x striptest
+	for x in cal date env free ls true uname uptime ; do
+		x=$(type -p ${x})
+		[[ -z ${x} || ${x} != ${EPREFIX}/* ]] && continue
+		striptest=$(LC_ALL="C" file -L ${x} 2>/dev/null) || continue
+		case ${striptest} in
+		*"statically linked"*) continue;;
+		*"ASCII text"*) continue;;
+		esac
+		# We need to clear the locale settings as the upgrade might want
+		# incompatible locale data.  This test is not for verifying that.
+		LC_ALL=C \
+		./ld-*.so --library-path . ${x} > /dev/null \
+			|| die "simple run test (${x}) failed"
+	done
+
+	popd >/dev/null
+}
+
+pkg_preinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	# prepare /etc/ld.so.conf.d/ for files
+	mkdir -p "${EROOT}"/etc/ld.so.conf.d
+
+	# Default /etc/hosts.conf:multi to on for systems with small dbs.
+	if [[ $(wc -l < "${EROOT}"/etc/hosts) -lt 1000 ]] ; then
+		sed -i '/^multi off/s:off:on:' "${ED}"/etc/host.conf
+		einfo "Defaulting /etc/host.conf:multi to on"
+	fi
+
+	[[ -n ${ROOT} ]] && return 0
+	[[ -d ${ED}/$(get_libdir) ]] || return 0
+	[[ -z ${BOOTSTRAP_RAP} ]] && glibc_sanity_check
+}
+
+pkg_postinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	if ! tc-is-cross-compiler && [[ -x ${EROOT}/usr/sbin/iconvconfig ]] ; then
+		# Generate fastloading iconv module configuration file.
+		"${EROOT}"/usr/sbin/iconvconfig --prefix="${ROOT}/"
+	fi
+
+	if ! is_crosscompile && [[ -z ${ROOT} ]] ; then
+		use compile-locales || run_locale_gen "${EROOT}/"
+	fi
+
+	# Check for sanity of /etc/nsswitch.conf, take 2
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] && ! has_version sys-auth/libnss-nis ; then
+		local entry
+		for entry in passwd group shadow; do
+			if egrep -q "^[ \t]*${entry}:.*nis" "${EROOT}"/etc/nsswitch.conf; then
+				ewarn ""
+				ewarn "Your ${EROOT}/etc/nsswitch.conf uses NIS. Support for that has been"
+				ewarn "removed from glibc and is now provided by the package"
+				ewarn "  sys-auth/libnss-nis"
+				ewarn "Install it now to keep your NIS setup working."
+				ewarn ""
+			fi
+		done
+	fi
+}
diff --git a/sys-libs/glibc/glibc-2.31-r1.ebuild b/sys-libs/glibc/glibc-2.31-r1.ebuild
new file mode 100644
index 000000000000..14d8f5289a1d
--- /dev/null
+++ b/sys-libs/glibc/glibc-2.31-r1.ebuild
@@ -0,0 +1,1493 @@
+# Copyright 1999-2020 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+PYTHON_COMPAT=( python3_{6,7,8} )
+
+inherit python-any-r1 prefix eutils toolchain-funcs flag-o-matic gnuconfig \
+	multilib systemd multiprocessing
+
+DESCRIPTION="GNU libc C library"
+HOMEPAGE="https://www.gnu.org/software/libc/"
+LICENSE="LGPL-2.1+ BSD HPND ISC inner-net rc PCRE"
+SLOT="2.2"
+
+EMULTILIB_PKG="true"
+
+if [[ ${PV} == 9999* ]]; then
+	EGIT_REPO_URI="https://sourceware.org/git/glibc.git"
+	inherit git-r3
+else
+	# needs minimal testing
+	#KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sh ~sparc ~x86"
+	SRC_URI="mirror://gnu/glibc/${P}.tar.xz"
+fi
+
+RELEASE_VER=${PV}
+
+GCC_BOOTSTRAP_VER=20180511
+
+# Gentoo patchset
+PATCH_VER=2
+PATCH_DEV=slyfox
+
+SRC_URI+=" https://dev.gentoo.org/~${PATCH_DEV}/distfiles/${P}-patches-${PATCH_VER}.tar.xz"
+SRC_URI+=" multilib? ( https://dev.gentoo.org/~dilfridge/distfiles/gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz )"
+
+IUSE="audit caps cet compile-locales +crypt custom-cflags doc gd headers-only +multiarch multilib nscd profile selinux +ssp +static-libs suid systemtap test vanilla"
+
+# Minimum kernel version that glibc requires
+MIN_KERN_VER="3.2.0"
+
+# Here's how the cross-compile logic breaks down ...
+#  CTARGET - machine that will target the binaries
+#  CHOST   - machine that will host the binaries
+#  CBUILD  - machine that will build the binaries
+# If CTARGET != CHOST, it means you want a libc for cross-compiling.
+# If CHOST != CBUILD, it means you want to cross-compile the libc.
+#  CBUILD = CHOST = CTARGET    - native build/install
+#  CBUILD != (CHOST = CTARGET) - cross-compile a native build
+#  (CBUILD = CHOST) != CTARGET - libc for cross-compiler
+#  CBUILD != CHOST != CTARGET  - cross-compile a libc for a cross-compiler
+# For install paths:
+#  CHOST = CTARGET  - install into /
+#  CHOST != CTARGET - install into /usr/CTARGET/
+#
+export CBUILD=${CBUILD:-${CHOST}}
+export CTARGET=${CTARGET:-${CHOST}}
+if [[ ${CTARGET} == ${CHOST} ]] ; then
+	if [[ ${CATEGORY} == cross-* ]] ; then
+		export CTARGET=${CATEGORY#cross-}
+	fi
+fi
+
+# Note [Disable automatic stripping]
+# Disabling automatic stripping for a few reasons:
+# - portage's attempt to strip breaks non-native binaries at least on
+#   arm: bug #697428
+# - portage's attempt to strip libpthread.so.0 breaks gdb thread
+#   enumeration: bug #697910. This is quite subtle:
+#   * gdb uses glibc's libthread_db-1.0.so to enumerate threads.
+#   * libthread_db-1.0.so needs access to libpthread.so.0 local symbols
+#     via 'ps_pglobal_lookup' symbol defined in gdb.
+#   * 'ps_pglobal_lookup' uses '.symtab' section table to resolve all
+#     known symbols in 'libpthread.so.0'. Specifically 'nptl_version'
+#     (unexported) is used to sanity check compatibility before enabling
+#     debugging.
+#     Also see https://sourceware.org/gdb/wiki/FAQ#GDB_does_not_see_any_threads_besides_the_one_in_which_crash_occurred.3B_or_SIGTRAP_kills_my_program_when_I_set_a_breakpoint
+#   * normal 'strip' command trims '.symtab'
+#   Thus our main goal here is to prevent 'libpthread.so.0' from
+#   losing it's '.symtab' entries.
+# As Gentoo's strip does not allow us to pass less aggressive stripping
+# options and does not check the machine target we strip selectively.
+
+# We need a new-enough binutils/gcc to match upstream baseline.
+# Also we need to make sure our binutils/gcc supports TLS,
+# and that gcc already contains the hardened patches.
+BDEPEND="
+	${PYTHON_DEPS}
+	>=app-misc/pax-utils-0.1.10
+	sys-devel/bison
+	!<sys-devel/bison-2.7
+	!<sys-devel/make-4
+	doc? ( sys-apps/texinfo )
+"
+COMMON_DEPEND="
+	gd? ( media-libs/gd:2= )
+	nscd? ( selinux? (
+		audit? ( sys-process/audit )
+		caps? ( sys-libs/libcap )
+	) )
+	suid? ( caps? ( sys-libs/libcap ) )
+	selinux? ( sys-libs/libselinux )
+	systemtap? ( dev-util/systemtap )
+"
+DEPEND="${COMMON_DEPEND}
+	test? ( >=net-dns/libidn2-2.0.5 )
+"
+RDEPEND="${COMMON_DEPEND}
+	sys-apps/gentoo-functions
+"
+
+RESTRICT="!test? ( test )"
+
+if [[ ${CATEGORY} == cross-* ]] ; then
+	BDEPEND+=" !headers-only? (
+		>=${CATEGORY}/binutils-2.24
+		>=${CATEGORY}/gcc-6
+	)"
+	[[ ${CATEGORY} == *-linux* ]] && DEPEND+=" ${CATEGORY}/linux-headers"
+else
+	BDEPEND+="
+		>=sys-devel/binutils-2.24
+		>=sys-devel/gcc-6
+	"
+	DEPEND+=" virtual/os-headers "
+	RDEPEND+="
+		>=net-dns/libidn2-2.0.5
+		vanilla? ( !sys-libs/timezone-data )
+	"
+	PDEPEND+=" !vanilla? ( sys-libs/timezone-data )"
+fi
+
+#
+# Small helper functions
+#
+
+is_crosscompile() {
+	[[ ${CHOST} != ${CTARGET} ]]
+}
+
+just_headers() {
+	is_crosscompile && use headers-only
+}
+
+alt_prefix() {
+	is_crosscompile && echo /usr/${CTARGET}
+}
+
+# This prefix is applicable to CHOST when building against this
+# glibc. It is baked into the library at configure time.
+host_eprefix() {
+	is_crosscompile || echo "${EPREFIX}"
+}
+
+# This prefix is applicable to CBUILD when building against this
+# glibc. It determines the destination path at install time.
+build_eprefix() {
+	is_crosscompile && echo "${EPREFIX}"
+}
+
+# We need to be able to set alternative headers for compiling for non-native
+# platform. Will also become useful for testing kernel-headers without screwing
+# up the whole system.
+alt_headers() {
+	echo ${ALT_HEADERS:=$(alt_prefix)/usr/include}
+}
+
+alt_build_headers() {
+	if [[ -z ${ALT_BUILD_HEADERS} ]] ; then
+		ALT_BUILD_HEADERS="$(host_eprefix)$(alt_headers)"
+		if tc-is-cross-compiler ; then
+			ALT_BUILD_HEADERS=${SYSROOT}$(alt_headers)
+			if [[ ! -e ${ALT_BUILD_HEADERS}/linux/version.h ]] ; then
+				local header_path=$(echo '#include <linux/version.h>' | $(tc-getCPP ${CTARGET}) ${CFLAGS} 2>&1 | grep -o '[^"]*linux/version.h')
+				ALT_BUILD_HEADERS=${header_path%/linux/version.h}
+			fi
+		fi
+	fi
+	echo "${ALT_BUILD_HEADERS}"
+}
+
+alt_libdir() {
+	echo $(alt_prefix)/$(get_libdir)
+}
+alt_usrlibdir() {
+	echo $(alt_prefix)/usr/$(get_libdir)
+}
+
+builddir() {
+	echo "${WORKDIR}/build-${ABI}-${CTARGET}-$1"
+}
+
+do_compile_test() {
+	local ret save_cflags=${CFLAGS}
+	CFLAGS+=" $1"
+	shift
+
+	pushd "${T}" >/dev/null
+
+	rm -f glibc-test*
+	printf '%b' "$*" > glibc-test.c
+
+	nonfatal emake glibc-test
+	ret=$?
+
+	popd >/dev/null
+
+	CFLAGS=${save_cflags}
+	return ${ret}
+}
+
+do_run_test() {
+	local ret
+
+	if [[ ${MERGE_TYPE} == "binary" ]] ; then
+		# ignore build failures when installing a binary package #324685
+		do_compile_test "" "$@" 2>/dev/null || return 0
+	else
+		if ! do_compile_test "" "$@" ; then
+			ewarn "Simple build failed ... assuming this is desired #324685"
+			return 0
+		fi
+	fi
+
+	pushd "${T}" >/dev/null
+
+	./glibc-test
+	ret=$?
+	rm -f glibc-test*
+
+	popd >/dev/null
+
+	return ${ret}
+}
+
+setup_target_flags() {
+	# This largely mucks with compiler flags.  None of which should matter
+	# when building up just the headers.
+	just_headers && return 0
+
+	case $(tc-arch) in
+		x86)
+			# -march needed for #185404 #199334
+			# TODO: When creating the first glibc cross-compile, this test will
+			# always fail as it does a full link which in turn requires glibc.
+			# Probably also applies when changing multilib profile settings (e.g.
+			# enabling x86 when the profile was amd64-only previously).
+			# We could change main to _start and pass -nostdlib here so that we
+			# only test the gcc code compilation.  Or we could do a compile and
+			# then look for the symbol via scanelf.
+			if ! do_compile_test "" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+				local t=${CTARGET_OPT:-${CTARGET}}
+				t=${t%%-*}
+				filter-flags '-march=*'
+				export CFLAGS="-march=${t} ${CFLAGS}"
+				einfo "Auto adding -march=${t} to CFLAGS #185404"
+			fi
+		;;
+		amd64)
+			# -march needed for #185404 #199334
+			# TODO: See cross-compile issues listed above for x86.
+			[[ ${ABI} == x86 ]] &&
+			if ! do_compile_test "${CFLAGS_x86}" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+				local t=${CTARGET_OPT:-${CTARGET}}
+				t=${t%%-*}
+				# Normally the target is x86_64-xxx, so turn that into the -march that
+				# gcc actually accepts. #528708
+				[[ ${t} == "x86_64" ]] && t="x86-64"
+				filter-flags '-march=*'
+				# ugly, ugly, ugly.  ugly.
+				CFLAGS_x86=$(CFLAGS=${CFLAGS_x86} filter-flags '-march=*'; echo "${CFLAGS}")
+				export CFLAGS_x86="${CFLAGS_x86} -march=${t}"
+				einfo "Auto adding -march=${t} to CFLAGS_x86 #185404 (ABI=${ABI})"
+			fi
+		;;
+		mips)
+			# The mips abi cannot support the GNU style hashes. #233233
+			filter-ldflags -Wl,--hash-style=gnu -Wl,--hash-style=both
+		;;
+		sparc)
+			# Both sparc and sparc64 can use -fcall-used-g6.  -g7 is bad, though.
+			filter-flags "-fcall-used-g7"
+			append-flags "-fcall-used-g6"
+
+			# If the CHOST is the basic one (e.g. not sparcv9-xxx already),
+			# try to pick a better one so glibc can use cpu-specific .S files.
+			# We key off the CFLAGS to get a good value.  Also need to handle
+			# version skew.
+			# We can't force users to set their CHOST to their exact machine
+			# as many of these are not recognized by config.sub/gcc and such :(.
+			# Note: If the mcpu values don't scale, we might try probing CPP defines.
+			# Note: Should we factor in -Wa,-AvXXX flags too ?  Or -mvis/etc... ?
+
+			local cpu
+			case ${CTARGET} in
+			sparc64-*)
+				case $(get-flag mcpu) in
+				niagara[234])
+					if ver_test -ge 2.8 ; then
+						cpu="sparc64v2"
+					elif ver_test -ge 2.4 ; then
+						cpu="sparc64v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparc64b"
+					fi
+					;;
+				niagara)
+					if ver_test -ge 2.4 ; then
+						cpu="sparc64v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparc64b"
+					fi
+					;;
+				ultrasparc3)
+					cpu="sparc64b"
+					;;
+				*)
+					# We need to force at least v9a because the base build doesn't
+					# work with just v9.
+					# https://sourceware.org/bugzilla/show_bug.cgi?id=19477
+					[[ -z ${cpu} ]] && append-flags "-Wa,-xarch=v9a"
+					;;
+				esac
+				;;
+			sparc-*)
+				case $(get-flag mcpu) in
+				niagara[234])
+					if ver_test -ge 2.8 ; then
+						cpu="sparcv9v2"
+					elif ver_test -ge 2.4 ; then
+						cpu="sparcv9v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparcv9b"
+					else
+						cpu="sparcv9"
+					fi
+					;;
+				niagara)
+					if ver_test -ge 2.4 ; then
+						cpu="sparcv9v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparcv9b"
+					else
+						cpu="sparcv9"
+					fi
+					;;
+				ultrasparc3)
+					cpu="sparcv9b"
+					;;
+				v9|ultrasparc)
+					cpu="sparcv9"
+					;;
+				v8|supersparc|hypersparc|leon|leon3)
+					cpu="sparcv8"
+					;;
+				esac
+			;;
+			esac
+			[[ -n ${cpu} ]] && CTARGET_OPT="${cpu}-${CTARGET#*-}"
+		;;
+	esac
+}
+
+setup_flags() {
+	# Make sure host make.conf doesn't pollute us
+	if is_crosscompile || tc-is-cross-compiler ; then
+		CHOST=${CTARGET} strip-unsupported-flags
+	fi
+
+	# Store our CFLAGS because it's changed depending on which CTARGET
+	# we are building when pulling glibc on a multilib profile
+	CFLAGS_BASE=${CFLAGS_BASE-${CFLAGS}}
+	CFLAGS=${CFLAGS_BASE}
+	CXXFLAGS_BASE=${CXXFLAGS_BASE-${CXXFLAGS}}
+	CXXFLAGS=${CXXFLAGS_BASE}
+	ASFLAGS_BASE=${ASFLAGS_BASE-${ASFLAGS}}
+	ASFLAGS=${ASFLAGS_BASE}
+
+	# Allow users to explicitly avoid flag sanitization via
+	# USE=custom-cflags.
+	if ! use custom-cflags; then
+		# Over-zealous CFLAGS can often cause problems.  What may work for one
+		# person may not work for another.  To avoid a large influx of bugs
+		# relating to failed builds, we strip most CFLAGS out to ensure as few
+		# problems as possible.
+		strip-flags
+		# Lock glibc at -O2; we want to be conservative here.
+		filter-flags '-O?'
+		append-flags -O2
+	fi
+	strip-unsupported-flags
+	filter-flags -m32 -m64 '-mabi=*'
+
+	# glibc aborts if rpath is set by LDFLAGS
+	filter-ldflags '-Wl,-rpath=*'
+
+	# #492892
+	filter-flags -frecord-gcc-switches
+
+	unset CBUILD_OPT CTARGET_OPT
+	if use multilib ; then
+		CTARGET_OPT=$(get_abi_CTARGET)
+		[[ -z ${CTARGET_OPT} ]] && CTARGET_OPT=$(get_abi_CHOST)
+	fi
+
+	setup_target_flags
+
+	if [[ -n ${CTARGET_OPT} && ${CBUILD} == ${CHOST} ]] && ! is_crosscompile; then
+		CBUILD_OPT=${CTARGET_OPT}
+	fi
+
+	# glibc's headers disallow -O0 and fail at build time:
+	#  include/libc-symbols.h:75:3: #error "glibc cannot be compiled without optimization"
+	replace-flags -O0 -O1
+
+	filter-flags '-fstack-protector*'
+}
+
+want_tls() {
+	# Archs that can use TLS (Thread Local Storage)
+	case $(tc-arch) in
+		x86)
+			# requires i486 or better #106556
+			[[ ${CTARGET} == i[4567]86* ]] && return 0
+			return 1
+		;;
+	esac
+	return 0
+}
+
+want__thread() {
+	want_tls || return 1
+
+	# For some reason --with-tls --with__thread is causing segfaults on sparc32.
+	[[ ${PROFILE_ARCH} == "sparc" ]] && return 1
+
+	[[ -n ${WANT__THREAD} ]] && return ${WANT__THREAD}
+
+	# only test gcc -- can't test linking yet
+	tc-has-tls -c ${CTARGET}
+	WANT__THREAD=$?
+
+	return ${WANT__THREAD}
+}
+
+use_multiarch() {
+	# Allow user to disable runtime arch detection in multilib.
+	use multiarch || return 1
+	# Make sure binutils is new enough to support indirect functions,
+	# #336792. This funky sed supports gold and bfd linkers.
+	local bver nver
+	bver=$($(tc-getLD ${CTARGET}) -v | sed -n -r '1{s:[^0-9]*::;s:^([0-9.]*).*:\1:;p}')
+	case $(tc-arch ${CTARGET}) in
+	amd64|x86) nver="2.20" ;;
+	arm)       nver="2.22" ;;
+	hppa)      nver="2.23" ;;
+	ppc|ppc64) nver="2.20" ;;
+	# ifunc support was added in 2.23, but glibc also needs
+	# machinemode which is in 2.24.
+	s390)      nver="2.24" ;;
+	sparc)     nver="2.21" ;;
+	*)         return 1 ;;
+	esac
+	ver_test ${bver} -ge ${nver}
+}
+
+# Setup toolchain variables that had historically been defined in the
+# profiles for these archs.
+setup_env() {
+	# silly users
+	unset LD_RUN_PATH
+	unset LD_ASSUME_KERNEL
+
+	if is_crosscompile || tc-is-cross-compiler ; then
+		multilib_env ${CTARGET_OPT:-${CTARGET}}
+
+		if ! use multilib ; then
+			MULTILIB_ABIS=${DEFAULT_ABI}
+		else
+			MULTILIB_ABIS=${MULTILIB_ABIS:-${DEFAULT_ABI}}
+		fi
+
+		# If the user has CFLAGS_<CTARGET> in their make.conf, use that,
+		# and fall back on CFLAGS.
+		local VAR=CFLAGS_${CTARGET//[-.]/_}
+		CFLAGS=${!VAR-${CFLAGS}}
+		einfo " $(printf '%15s' 'Manual CFLAGS:')   ${CFLAGS}"
+	fi
+
+	setup_flags
+
+	export ABI=${ABI:-${DEFAULT_ABI:-default}}
+
+	if just_headers ; then
+		# Avoid mixing host's CC and target's CFLAGS_${ABI}:
+		# At this bootstrap stage we have only binutils for
+		# target but not compiler yet.
+		einfo "Skip CC ABI injection. We can't use (cross-)compiler yet."
+		return 0
+	fi
+	local VAR=CFLAGS_${ABI}
+	# We need to export CFLAGS with abi information in them because glibc's
+	# configure script checks CFLAGS for some targets (like mips).  Keep
+	# around the original clean value to avoid appending multiple ABIs on
+	# top of each other.
+	: ${__GLIBC_CC:=$(tc-getCC ${CTARGET_OPT:-${CTARGET}})}
+	export __GLIBC_CC CC="${__GLIBC_CC} ${!VAR}"
+	einfo " $(printf '%15s' 'Manual CC:')   ${CC}"
+}
+
+foreach_abi() {
+	setup_env
+
+	local ret=0
+	local abilist=""
+	if use multilib ; then
+		abilist=$(get_install_abis)
+	else
+		abilist=${DEFAULT_ABI}
+	fi
+	local -x ABI
+	for ABI in ${abilist:-default} ; do
+		setup_env
+		einfo "Running $1 for ABI ${ABI}"
+		$1
+		: $(( ret |= $? ))
+	done
+	return ${ret}
+}
+
+glibc_banner() {
+	local b="Gentoo ${PVR}"
+	[[ -n ${PATCH_VER} ]] && ! use vanilla && b+=" p${PATCH_VER}"
+	echo "${b}"
+}
+
+check_devpts() {
+	# Make sure devpts is mounted correctly for use w/out setuid pt_chown.
+
+	# If merely building the binary package, then there's nothing to verify.
+	[[ ${MERGE_TYPE} == "buildonly" ]] && return
+
+	# Only sanity check when installing the native glibc.
+	[[ -n ${ROOT} ]] && return
+
+	# If they're opting in to the old suid code, then no need to check.
+	use suid && return
+
+	if awk '$3 == "devpts" && $4 ~ /[, ]gid=5[, ]/ { exit 1 }' /proc/mounts ; then
+		eerror "In order to use glibc with USE=-suid, you must make sure that"
+		eerror "you have devpts mounted at /dev/pts with the gid=5 option."
+		eerror "Openrc should do this for you, so you should check /etc/fstab"
+		eerror "and make sure you do not have any invalid settings there."
+		die "mount & fix your /dev/pts settings"
+	fi
+}
+
+# The following Kernel version handling functions are mostly copied from portage
+# source. It's better not to use linux-info.eclass here since a) it adds too
+# much magic, see bug 326693 for some of the arguments, and b) some of the
+# functions are just not provided.
+
+g_get_running_KV() {
+	uname -r
+	return $?
+}
+
+g_KV_major() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	echo "${KV%%.*}"
+}
+
+g_KV_minor() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.}
+	echo "${KV%%.*}"
+}
+
+g_KV_micro() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.*.}
+	echo "${KV%%[^[:digit:]]*}"
+}
+
+g_KV_to_int() {
+	[[ -z $1 ]] && return 1
+	local KV_MAJOR=$(g_KV_major "$1")
+	local KV_MINOR=$(g_KV_minor "$1")
+	local KV_MICRO=$(g_KV_micro "$1")
+	local KV_int=$(( KV_MAJOR * 65536 + KV_MINOR * 256 + KV_MICRO ))
+
+	# We make version 2.2.0 the minimum version we will handle as
+	# a sanity check ... if its less, we fail ...
+	if [[ ${KV_int} -ge 131584 ]] ; then
+		echo "${KV_int}"
+		return 0
+	fi
+	return 1
+}
+
+g_int_to_KV() {
+	local version=$1 major minor micro
+	major=$((version / 65536))
+	minor=$(((version % 65536) / 256))
+	micro=$((version % 256))
+	echo ${major}.${minor}.${micro}
+}
+
+eend_KV() {
+	[[ $(g_KV_to_int $1) -ge $(g_KV_to_int $2) ]]
+	eend $?
+}
+
+get_kheader_version() {
+	printf '#include <linux/version.h>\nLINUX_VERSION_CODE\n' | \
+	$(tc-getCPP ${CTARGET}) -I "$(build_eprefix)$(alt_build_headers)" - | \
+	tail -n 1
+}
+
+# We collect all sanity checks here. Consistency is not guranteed between
+# pkg_ and src_ phases, so we call this function both in pkg_pretend and in
+# src_unpack.
+sanity_prechecks() {
+	# Make sure devpts is mounted correctly for use w/out setuid pt_chown
+	check_devpts
+
+	# Prevent native builds from downgrading
+	if [[ ${MERGE_TYPE} != "buildonly" ]] && \
+	   [[ -z ${ROOT} ]] && \
+	   [[ ${CBUILD} == ${CHOST} ]] && \
+	   [[ ${CHOST} == ${CTARGET} ]] ; then
+
+		# The high rev # is to allow people to downgrade between -r#
+		# versions. We want to block 2.20->2.19, but 2.20-r3->2.20-r2
+		# should be fine. Hopefully we never actually use a r# this
+		# high.
+		if has_version ">${CATEGORY}/${P}-r10000" ; then
+			eerror "Sanity check to keep you from breaking your system:"
+			eerror " Downgrading glibc is not supported and a sure way to destruction."
+			[[ ${I_ALLOW_TO_BREAK_MY_SYSTEM} = yes ]] || die "Aborting to save your system."
+		fi
+
+		if ! do_run_test '#include <unistd.h>\n#include <sys/syscall.h>\nint main(){return syscall(1000)!=-1;}\n' ; then
+			eerror "Your old kernel is broken. You need to update it to a newer"
+			eerror "version as syscall(<bignum>) will break. See bug 279260."
+			die "Old and broken kernel."
+		fi
+	fi
+
+	# Users have had a chance to phase themselves, time to give em the boot
+	if [[ -e ${EROOT}/etc/locale.gen ]] && [[ -e ${EROOT}/etc/locales.build ]] ; then
+		eerror "You still haven't deleted ${EROOT}/etc/locales.build."
+		eerror "Do so now after making sure ${EROOT}/etc/locale.gen is kosher."
+		die "Lazy upgrader detected"
+	fi
+
+	if [[ ${CTARGET} == i386-* ]] ; then
+		eerror "i386 CHOSTs are no longer supported."
+		eerror "Chances are you don't actually want/need i386."
+		eerror "Please read https://www.gentoo.org/doc/en/change-chost.xml"
+		die "Please fix your CHOST"
+	fi
+
+	if [[ -e /proc/xen ]] && [[ $(tc-arch) == "x86" ]] && ! is-flag -mno-tls-direct-seg-refs ; then
+		ewarn "You are using Xen but don't have -mno-tls-direct-seg-refs in your CFLAGS."
+		ewarn "This will result in a 50% performance penalty when running with a 32bit"
+		ewarn "hypervisor, which is probably not what you want."
+	fi
+
+	# Check for sanity of /etc/nsswitch.conf
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] ; then
+		local entry
+		for entry in passwd group shadow; do
+			if ! egrep -q "^[ \t]*${entry}:.*files" "${EROOT}"/etc/nsswitch.conf; then
+				eerror "Your ${EROOT}/etc/nsswitch.conf is out of date."
+				eerror "Please make sure you have 'files' entries for"
+				eerror "'passwd:', 'group:' and 'shadow:' databases."
+				eerror "For more details see:"
+				eerror "  https://wiki.gentoo.org/wiki/Project:Toolchain/nsswitch.conf_in_glibc-2.26"
+				die "nsswitch.conf has no 'files' provider in '${entry}'."
+			fi
+		done
+	fi
+
+	# ABI-specific checks follow here. Hey, we have a lot more specific conditions that
+	# we test for...
+	if ! is_crosscompile ; then
+		if use amd64 && use multilib && [[ ${MERGE_TYPE} != "binary" ]] ; then
+			ebegin "Checking that IA32 emulation is enabled in the running kernel"
+			echo 'int main(){return 0;}' > "${T}/check-ia32-emulation.c"
+			local STAT
+			if "${CC-${CHOST}-gcc}" ${CFLAGS_x86} "${T}/check-ia32-emulation.c" -o "${T}/check-ia32-emulation.elf32"; then
+				"${T}/check-ia32-emulation.elf32"
+				STAT=$?
+			else
+				# Don't fail here to allow single->multi ABI switch
+				# or recover from breakage like bug #646424
+				ewarn "Failed to compile the ABI test. Broken host glibc?"
+				STAT=0
+			fi
+			rm -f "${T}/check-ia32-emulation.elf32"
+			eend $STAT
+			[[ $STAT -eq 0 ]] || die "CONFIG_IA32_EMULATION must be enabled in the kernel to compile a multilib glibc."
+		fi
+
+	fi
+
+	# When we actually have to compile something...
+	if ! just_headers ; then
+		ebegin "Checking gcc for __thread support"
+		if ! eend $(want__thread ; echo $?) ; then
+			echo
+			eerror "Could not find a gcc that supports the __thread directive!"
+			eerror "Please update your binutils/gcc and try again."
+			die "No __thread support in gcc!"
+		fi
+
+		if [[ ${CTARGET} == *-linux* ]] ; then
+			local run_kv build_kv want_kv
+
+			run_kv=$(g_get_running_KV)
+			build_kv=$(g_int_to_KV $(get_kheader_version))
+			want_kv=${MIN_KERN_VER}
+
+			if ! is_crosscompile && ! tc-is-cross-compiler ; then
+				# Building fails on an non-supporting kernel
+				ebegin "Checking running kernel version (${run_kv} >= ${want_kv})"
+				if ! eend_KV ${run_kv} ${want_kv} ; then
+					echo
+					eerror "You need a kernel of at least ${want_kv}!"
+					die "Kernel version too low!"
+				fi
+			fi
+
+			ebegin "Checking linux-headers version (${build_kv} >= ${want_kv})"
+			if ! eend_KV ${build_kv} ${want_kv} ; then
+				echo
+				eerror "You need linux-headers of at least ${want_kv}!"
+				die "linux-headers version too low!"
+			fi
+		fi
+	fi
+}
+
+#
+# the phases
+#
+
+# pkg_pretend
+
+pkg_pretend() {
+	# All the checks...
+	einfo "Checking general environment sanity."
+	sanity_prechecks
+}
+
+pkg_setup() {
+	# see bug 682570
+	[[ -z ${BOOTSTRAP_RAP} ]] && python-any-r1_pkg_setup
+}
+
+# src_unpack
+
+src_unpack() {
+	# Consistency is not guaranteed between pkg_ and src_ ...
+	sanity_prechecks
+
+	use multilib && unpack gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz
+
+	setup_env
+
+	if [[ -n ${EGIT_REPO_URI} ]] ; then
+		git-r3_src_unpack
+	else
+		unpack ${P}.tar.xz
+	fi
+
+	cd "${WORKDIR}" || die
+	unpack glibc-${RELEASE_VER}-patches-${PATCH_VER}.tar.xz
+}
+
+src_prepare() {
+	if ! use vanilla ; then
+		elog "Applying Gentoo Glibc Patchset ${RELEASE_VER}-${PATCH_VER}"
+		eapply "${WORKDIR}"/patches
+		einfo "Done."
+	fi
+
+	default
+
+	gnuconfig_update
+
+	cd "${WORKDIR}"
+	find . -name configure -exec touch {} +
+
+	eprefixify extra/locale/locale-gen
+
+	# Fix permissions on some of the scripts.
+	chmod u+x "${S}"/scripts/*.sh
+
+	cd "${S}"
+}
+
+glibc_do_configure() {
+	# Glibc does not work with gold (for various reasons) #269274.
+	tc-ld-disable-gold
+
+	# CXX isnt handled by the multilib system, so if we dont unset here
+	# we accumulate crap across abis
+	unset CXX
+
+	einfo "Configuring glibc for nptl"
+
+	if use doc ; then
+		export MAKEINFO=makeinfo
+	else
+		export MAKEINFO=/dev/null
+	fi
+
+	local v
+	for v in ABI CBUILD CHOST CTARGET CBUILD_OPT CTARGET_OPT CC CXX LD {AS,C,CPP,CXX,LD}FLAGS MAKEINFO ; do
+		einfo " $(printf '%15s' ${v}:)   ${!v}"
+	done
+
+	# CFLAGS can contain ABI-specific flags like -mfpu=neon, see bug #657760
+	# To build .S (assembly) files with the same ABI-specific flags
+	# upstream currently recommends adding CFLAGS to CC/CXX:
+	#    https://sourceware.org/PR23273
+	# Note: Passing CFLAGS via CPPFLAGS overrides glibc's arch-specific CFLAGS
+	# and breaks multiarch support. See 659030#c3 for an example.
+	# The glibc configure script doesn't properly use LDFLAGS all the time.
+	export CC="$(tc-getCC ${CTARGET}) ${CFLAGS} ${LDFLAGS}"
+	einfo " $(printf '%15s' 'Manual CC:')   ${CC}"
+
+	# Some of the tests are written in C++, so we need to force our multlib abis in, bug 623548
+	export CXX="$(tc-getCXX ${CTARGET}) $(get_abi_CFLAGS) ${CFLAGS}"
+
+	if is_crosscompile; then
+		# Assume worst-case bootstrap: glibc is buil first time
+		# when ${CTARGET}-g++ is not available yet. We avoid
+		# building auxiliary programs that require C++: bug #683074
+		# It should not affect final result.
+		export libc_cv_cxx_link_ok=no
+		# The line above has the same effect. We set CXX explicitly
+		# to make build logs less confusing.
+		export CXX=
+	fi
+	einfo " $(printf '%15s' 'Manual CXX:')   ${CXX}"
+
+	echo
+
+	local myconf=()
+
+	case ${CTARGET} in
+		m68k*)
+			# setjmp() is not compatible with stack protection:
+			# https://sourceware.org/PR24202
+			myconf+=( --enable-stack-protector=no )
+			;;
+		powerpc-*)
+			# Currently gcc on powerpc32 generates invalid code for
+			# __builtin_return_address(0) calls. Normally programs
+			# don't do that but malloc hooks in glibc do:
+			# https://gcc.gnu.org/PR81996
+			# https://bugs.gentoo.org/629054
+			myconf+=( --enable-stack-protector=no )
+			;;
+		*)
+			myconf+=( --enable-stack-protector=$(usex ssp all no) )
+			;;
+	esac
+	myconf+=( --enable-stackguard-randomization )
+
+	# Keep a whitelist of targets supporing IFUNC. glibc's ./configure
+	# is not robust enough to detect proper support:
+	#    https://bugs.gentoo.org/641216
+	#    https://sourceware.org/PR22634#c0
+	case $(tc-arch ${CTARGET}) in
+		# Keep whitelist of targets where autodetection mostly works.
+		amd64|x86|sparc|ppc|ppc64|arm|arm64|s390) ;;
+		# Blacklist everywhere else
+		*) myconf+=( libc_cv_ld_gnu_indirect_function=no ) ;;
+	esac
+
+	# Enable Intel Control-flow Enforcement Technology on amd64 if requested
+	case ${CTARGET} in
+		x86_64-*) myconf+=( $(use_enable cet) ) ;;
+		*) ;;
+	esac
+
+	[[ $(tc-is-softfloat) == "yes" ]] && myconf+=( --without-fp )
+
+	myconf+=( --enable-kernel=${MIN_KERN_VER} )
+
+	# Since SELinux support is only required for nscd, only enable it if:
+	# 1. USE selinux
+	# 2. only for the primary ABI on multilib systems
+	# 3. Not a crosscompile
+	if ! is_crosscompile && use selinux ; then
+		if use multilib ; then
+			if is_final_abi ; then
+				myconf+=( --with-selinux )
+			else
+				myconf+=( --without-selinux )
+			fi
+		else
+			myconf+=( --with-selinux )
+		fi
+	else
+		myconf+=( --without-selinux )
+	fi
+
+	# Force a few tests where we always know the answer but
+	# configure is incapable of finding it.
+	if is_crosscompile ; then
+		export \
+			libc_cv_c_cleanup=yes \
+			libc_cv_forced_unwind=yes
+	fi
+
+	myconf+=(
+		--without-cvs
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		$(use_enable profile)
+		$(use_with gd)
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		--sysconfdir="$(host_eprefix)/etc"
+		--localstatedir="$(host_eprefix)/var"
+		--libdir='$(prefix)'/$(get_libdir)
+		--mandir='$(prefix)'/share/man
+		--infodir='$(prefix)'/share/info
+		--libexecdir='$(libdir)'/misc/glibc
+		--with-bugurl=https://bugs.gentoo.org/
+		--with-pkgversion="$(glibc_banner)"
+		$(use_enable crypt)
+		$(use_multiarch || echo --disable-multi-arch)
+		$(use_enable systemtap)
+		$(use_enable nscd)
+		${EXTRA_ECONF}
+	)
+
+	# We rely on sys-libs/timezone-data for timezone tools normally.
+	myconf+=( $(use_enable vanilla timezone-tools) )
+
+	# These libs don't have configure flags.
+	ac_cv_lib_audit_audit_log_user_avc_message=$(usex audit || echo no)
+	ac_cv_lib_cap_cap_init=$(usex caps || echo no)
+
+	# There is no configure option for this and we need to export it
+	# since the glibc build will re-run configure on itself
+	export libc_cv_rootsbindir="$(host_eprefix)/sbin"
+	export libc_cv_slibdir="$(host_eprefix)/$(get_libdir)"
+
+	# We take care of patching our binutils to use both hash styles,
+	# and many people like to force gnu hash style only, so disable
+	# this overriding check.  #347761
+	export libc_cv_hashstyle=no
+
+	local builddir=$(builddir nptl)
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+	set -- "${S}"/configure "${myconf[@]}"
+	echo "$@"
+	"$@" || die "failed to configure glibc"
+
+	# ia64 static cross-compilers are a pita in so much that they
+	# can't produce static ELFs (as the libgcc.a is broken).  so
+	# disable building of the programs for those targets if it
+	# doesn't work.
+	# XXX: We could turn this into a compiler test, but ia64 is
+	# the only one that matters, so this should be fine for now.
+	if is_crosscompile && [[ ${CTARGET} == ia64* ]] ; then
+		sed -i '1i+link-static = touch $@' config.make
+	fi
+
+	# If we're trying to migrate between ABI sets, we need
+	# to lie and use a local copy of gcc.  Like if the system
+	# is built with MULTILIB_ABIS="amd64 x86" but we want to
+	# add x32 to it, gcc/glibc don't yet support x32.
+	#
+	if [[ -n ${GCC_BOOTSTRAP_VER} ]] && use multilib ; then
+		echo 'main(){}' > "${T}"/test.c
+		if ! $(tc-getCC ${CTARGET}) ${CFLAGS} ${LDFLAGS} "${T}"/test.c -Wl,-emain -lgcc 2>/dev/null ; then
+			sed -i -e '/^CC = /s:$: -B$(objdir)/../'"gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}/${ABI}:" config.make || die
+		fi
+	fi
+}
+
+glibc_headers_configure() {
+	export ABI=default
+
+	local builddir=$(builddir "headers")
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+
+	# if we don't have a compiler yet, we can't really test it now ...
+	# hopefully they don't affect header generation, so let's hope for
+	# the best here ...
+	local v vars=(
+		ac_cv_header_cpuid_h=yes
+		libc_cv_{386,390,alpha,arm,hppa,ia64,mips,{powerpc,sparc}{,32,64},sh,x86_64}_tls=yes
+		libc_cv_asm_cfi_directives=yes
+		libc_cv_broken_visibility_attribute=no
+		libc_cv_c_cleanup=yes
+		libc_cv_compiler_powerpc64le_binary128_ok=yes
+		libc_cv_forced_unwind=yes
+		libc_cv_gcc___thread=yes
+		libc_cv_mlong_double_128=yes
+		libc_cv_mlong_double_128ibm=yes
+		libc_cv_ppc_machine=yes
+		libc_cv_ppc_rel16=yes
+		libc_cv_predef_fortify_source=no
+		libc_cv_target_power8_ok=yes
+		libc_cv_visibility_attribute=yes
+		libc_cv_z_combreloc=yes
+		libc_cv_z_execstack=yes
+		libc_cv_z_initfirst=yes
+		libc_cv_z_nodelete=yes
+		libc_cv_z_nodlopen=yes
+		libc_cv_z_relro=yes
+		libc_mips_abi=${ABI}
+		libc_mips_float=$([[ $(tc-is-softfloat) == "yes" ]] && echo soft || echo hard)
+		# These libs don't have configure flags.
+		ac_cv_lib_audit_audit_log_user_avc_message=no
+		ac_cv_lib_cap_cap_init=no
+	)
+
+	einfo "Forcing cached settings:"
+	for v in "${vars[@]}" ; do
+		einfo " ${v}"
+		export ${v}
+	done
+
+	local headers_only_arch_CPPFLAGS=()
+
+	# Blow away some random CC settings that screw things up. #550192
+	if [[ -d ${S}/sysdeps/mips ]]; then
+		pushd "${S}"/sysdeps/mips >/dev/null
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=32:' mips32/Makefile mips64/n32/Makefile || die
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=64:' mips64/n64/Makefile || die
+
+		# Force the mips ABI to the default.  This is OK because the set of
+		# installed headers in this phase is the same between the 3 ABIs.
+		# If this ever changes, this hack will break, but that's unlikely
+		# as glibc discourages that behavior.
+		# https://crbug.com/647033
+		sed -i -e 's:abiflag=.*:abiflag=_ABIO32:' preconfigure || die
+
+		popd >/dev/null
+	fi
+
+	case ${CTARGET} in
+	riscv*)
+		# RISC-V interrogates the compiler to determine which target to
+		# build.  If building the headers then we don't strictly need a
+		# RISC-V compiler, so the built-in definitions that are provided
+		# along with all RISC-V compiler might not exist.  This causes
+		# glibc's RISC-V preconfigure script to blow up.  Since we're just
+		# building the headers any value will actually work here, so just
+		# pick the standard one (rv64g/lp64d) to make the build scripts
+		# happy for now -- the headers are all the same anyway so it
+		# doesn't matter.
+		headers_only_arch_CPPFLAGS+=(
+			-D__riscv_xlen=64
+			-D__riscv_flen=64
+			-D__riscv_float_abi_double=1
+			-D__riscv_atomic=1
+		) ;;
+	esac
+
+	local myconf=()
+	myconf+=(
+		--disable-sanity-checks
+		--enable-hacker-mode
+		--without-cvs
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		${EXTRA_ECONF}
+	)
+
+	# Nothing is compiled here which would affect the headers for the target.
+	# So forcing CC/CFLAGS is sane.
+	local headers_only_CC=$(tc-getBUILD_CC)
+	local headers_only_CFLAGS="-O1 -pipe"
+	local headers_only_CPPFLAGS="-U_FORTIFY_SOURCE ${headers_only_arch_CPPFLAGS[*]}"
+	local headers_only_LDFLAGS=""
+	set -- "${S}"/configure "${myconf[@]}"
+	echo \
+		"CC=${headers_only_CC}" \
+		"CFLAGS=${headers_only_CFLAGS}" \
+		"CPPFLAGS=${headers_only_CPPFLAGS}" \
+		"LDFLAGS=${headers_only_LDFLAGS}" \
+		"$@"
+	CC=${headers_only_CC} \
+	CFLAGS=${headers_only_CFLAGS} \
+	CPPFLAGS=${headers_only_CPPFLAGS} \
+	LDFLAGS="" \
+	"$@" || die "failed to configure glibc"
+}
+
+do_src_configure() {
+	if just_headers ; then
+		glibc_headers_configure
+	else
+		glibc_do_configure nptl
+	fi
+}
+
+src_configure() {
+	foreach_abi do_src_configure
+}
+
+do_src_compile() {
+	emake -C "$(builddir nptl)"
+}
+
+src_compile() {
+	if just_headers ; then
+		return
+	fi
+
+	foreach_abi do_src_compile
+}
+
+glibc_src_test() {
+	cd "$(builddir nptl)"
+	emake check
+}
+
+do_src_test() {
+	local ret=0
+
+	glibc_src_test
+	: $(( ret |= $? ))
+
+	return ${ret}
+}
+
+src_test() {
+	if just_headers ; then
+		return
+	fi
+
+	# Give tests more time to complete.
+	export TIMEOUTFACTOR=5
+
+	foreach_abi do_src_test || die "tests failed"
+}
+
+run_locale_gen() {
+	# if the host locales.gen contains no entries, we'll install everything
+	local root="$1"
+	local inplace=""
+
+	if [[ "${root}" == "--inplace-glibc" ]] ; then
+		inplace="--inplace-glibc"
+		root="$2"
+	fi
+
+	local locale_list="${root}/etc/locale.gen"
+
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	if [[ -z $(locale-gen --list --config "${locale_list}") ]] ; then
+		[[ -z ${inplace} ]] && ewarn "Generating all locales; edit /etc/locale.gen to save time/space"
+		locale_list="${root}/usr/share/i18n/SUPPORTED"
+	fi
+
+	set -- locale-gen ${inplace} --jobs $(makeopts_jobs) --config "${locale_list}" \
+		--destdir "${root}"
+	echo "$@"
+	"$@"
+
+	popd >/dev/null
+}
+
+glibc_do_src_install() {
+	local builddir=$(builddir nptl)
+	cd "${builddir}"
+
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install
+
+	# This version (2.26) provides some compatibility libraries for the NIS/NIS+ support
+	# which come without headers etc. Only needed for binary packages since the
+	# external net-libs/libnsl has increased soversion. Keep only versioned libraries.
+	find "${D}" -name "libnsl.a" -delete
+	find "${D}" -name "libnsl.so" -delete
+
+	# Normally upstream_pv is ${PV}. Live ebuilds are exception, there we need
+	# to infer upstream version:
+	# '#define VERSION "2.26.90"' -> '2.26.90'
+	local upstream_pv=$(sed -n -r 's/#define VERSION "(.*)"/\1/p' "${S}"/version.h)
+
+	# Avoid stripping binaries not targeted by ${CHOST}. Or else
+	# ${CHOST}-strip would break binaries build for ${CTARGET}.
+	is_crosscompile && dostrip -x /
+	# gdb thread introspection relies on local libpthreas symbols. stripping breaks it
+	# See Note [Disable automatic stripping]
+	dostrip -x $(alt_libdir)/libpthread-${upstream_pv}.so
+
+	if [[ -e ${ED}/$(alt_usrlibdir)/libm-${upstream_pv}.a ]] ; then
+		# Move versioned .a file out of libdir to evade portage QA checks
+		# instead of using gen_usr_ldscript(). We fix ldscript as:
+		# "GROUP ( /usr/lib64/libm-<pv>.a ..." -> "GROUP ( /usr/lib64/glibc-<pv>/libm-<pv>.a ..."
+		sed -i "s@\(libm-${upstream_pv}.a\)@${P}/\1@" "${ED}"/$(alt_usrlibdir)/libm.a || die
+		dodir $(alt_usrlibdir)/${P}
+		mv "${ED}"/$(alt_usrlibdir)/libm-${upstream_pv}.a "${ED}"/$(alt_usrlibdir)/${P}/libm-${upstream_pv}.a || die
+	fi
+
+	# We'll take care of the cache ourselves
+	rm -f "${ED}"/etc/ld.so.cache
+
+	# Everything past this point just needs to be done once ...
+	is_final_abi || return 0
+
+	# Make sure the non-native interp can be found on multilib systems even
+	# if the main library set isn't installed into the right place.  Maybe
+	# we should query the active gcc for info instead of hardcoding it ?
+	local i ldso_abi ldso_name
+	local ldso_abi_list=(
+		# x86
+		amd64   /lib64/ld-linux-x86-64.so.2
+		x32     /libx32/ld-linux-x32.so.2
+		x86     /lib/ld-linux.so.2
+		# mips
+		o32     /lib/ld.so.1
+		n32     /lib32/ld.so.1
+		n64     /lib64/ld.so.1
+		# powerpc
+		ppc     /lib/ld.so.1
+		ppc64   /lib64/ld64.so.1
+		# riscv
+		lp64d   /lib/ld-linux-riscv64-lp64d.so.1
+		lp64    /lib/ld-linux-riscv64-lp64.so.1
+		# s390
+		s390    /lib/ld.so.1
+		s390x   /lib/ld64.so.1
+		# sparc
+		sparc32 /lib/ld-linux.so.2
+		sparc64 /lib64/ld-linux.so.2
+	)
+	case $(tc-endian) in
+	little)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64.so.1
+		)
+		;;
+	big)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64_be.so.1
+		)
+		;;
+	esac
+	if [[ ${SYMLINK_LIB} == "yes" ]] && [[ ! -e ${ED}/$(alt_prefix)/lib ]] ; then
+		dosym $(get_abi_LIBDIR ${DEFAULT_ABI}) $(alt_prefix)/lib
+	fi
+	for (( i = 0; i < ${#ldso_abi_list[@]}; i += 2 )) ; do
+		ldso_abi=${ldso_abi_list[i]}
+		has ${ldso_abi} $(get_install_abis) || continue
+
+		ldso_name="$(alt_prefix)${ldso_abi_list[i+1]}"
+		if [[ ! -L ${ED}/${ldso_name} && ! -e ${ED}/${ldso_name} ]] ; then
+			dosym ../$(get_abi_LIBDIR ${ldso_abi})/${ldso_name##*/} ${ldso_name}
+		fi
+	done
+
+	# With devpts under Linux mounted properly, we do not need the pt_chown
+	# binary to be setuid.  This is because the default owners/perms will be
+	# exactly what we want.
+	if ! use suid ; then
+		find "${ED}" -name pt_chown -exec chmod -s {} +
+	fi
+
+	#################################################################
+	# EVERYTHING AFTER THIS POINT IS FOR NATIVE GLIBC INSTALLS ONLY #
+	# Make sure we install some symlink hacks so that when we build
+	# a 2nd stage cross-compiler, gcc finds the target system
+	# headers correctly.  See gcc/doc/gccinstall.info
+	if is_crosscompile ; then
+		# We need to make sure that /lib and /usr/lib always exists.
+		# gcc likes to use relative paths to get to its multilibs like
+		# /usr/lib/../lib64/.  So while we don't install any files into
+		# /usr/lib/, we do need it to exist.
+		keepdir $(alt_prefix)/lib
+		keepdir $(alt_prefix)/usr/lib
+
+		dosym usr/include $(alt_prefix)/sys-include
+		return 0
+	fi
+
+	# Files for Debian-style locale updating
+	dodir /usr/share/i18n
+	sed \
+		-e "/^#/d" \
+		-e "/SUPPORTED-LOCALES=/d" \
+		-e "s: \\\\::g" -e "s:/: :g" \
+		"${S}"/localedata/SUPPORTED > "${ED}"/usr/share/i18n/SUPPORTED \
+		|| die "generating /usr/share/i18n/SUPPORTED failed"
+	cd "${WORKDIR}"/extra/locale
+	dosbin locale-gen
+	doman *.[0-8]
+	insinto /etc
+	doins locale.gen
+
+	# Make sure all the ABI's can find the locales and so we only
+	# have to generate one set
+	local a
+	keepdir /usr/$(get_libdir)/locale
+	for a in $(get_install_abis) ; do
+		if [[ ! -e ${ED}/usr/$(get_abi_LIBDIR ${a})/locale ]] ; then
+			dosym ../$(get_libdir)/locale /usr/$(get_abi_LIBDIR ${a})/locale
+		fi
+	done
+
+	# HACK: If we're building for riscv, we need to additionally make sure that
+	# we can find the locale archive afterwards
+	case ${CTARGET} in
+		riscv*)
+			if [[ ! -e ${ED}/usr/lib/locale ]] ; then
+				dosym ../$(get_libdir)/locale /usr/lib/locale
+			fi
+			;;
+		*) ;;
+	esac
+
+	cd "${S}"
+
+	# Install misc network config files
+	insinto /etc
+	doins nscd/nscd.conf posix/gai.conf nss/nsswitch.conf
+	doins "${WORKDIR}"/extra/etc/*.conf
+
+	if use nscd ; then
+		doinitd "$(prefixify_ro "${WORKDIR}"/extra/etc/nscd)"
+
+		local nscd_args=(
+			-e "s:@PIDFILE@:$(strings "${ED}"/usr/sbin/nscd | grep nscd.pid):"
+		)
+
+		sed -i "${nscd_args[@]}" "${ED}"/etc/init.d/nscd
+
+		systemd_dounit nscd/nscd.service
+		systemd_newtmpfilesd nscd/nscd.tmpfiles nscd.conf
+	else
+		# Do this since extra/etc/*.conf above might have nscd.conf.
+		rm -f "${ED}"/etc/nscd.conf
+	fi
+
+	echo 'LDPATH="include ld.so.conf.d/*.conf"' > "${T}"/00glibc
+	doenvd "${T}"/00glibc
+
+	for d in BUGS ChangeLog CONFORMANCE FAQ NEWS NOTES PROJECTS README* ; do
+		[[ -s ${d} ]] && dodoc ${d}
+	done
+	dodoc -r ChangeLog.old
+
+	# Prevent overwriting of the /etc/localtime symlink.  We'll handle the
+	# creation of the "factory" symlink in pkg_postinst().
+	rm -f "${ED}"/etc/localtime
+
+	# Generate all locales if this is a native build as locale generation
+	if use compile-locales && ! is_crosscompile ; then
+		run_locale_gen --inplace-glibc "${ED}/"
+		sed -e 's:COMPILED_LOCALES="":COMPILED_LOCALES="1":' -i "${ED}"/usr/sbin/locale-gen || die
+	fi
+}
+
+glibc_headers_install() {
+	local builddir=$(builddir "headers")
+	cd "${builddir}"
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install-headers
+
+	insinto $(alt_headers)/gnu
+	doins "${S}"/include/gnu/stubs.h
+
+	# Make sure we install the sys-include symlink so that when
+	# we build a 2nd stage cross-compiler, gcc finds the target
+	# system headers correctly.  See gcc/doc/gccinstall.info
+	dosym usr/include $(alt_prefix)/sys-include
+}
+
+src_install() {
+	if just_headers ; then
+		export ABI=default
+		glibc_headers_install
+		return
+	fi
+
+	foreach_abi glibc_do_src_install
+
+	if ! use static-libs ; then
+		elog "Not installing static glibc libraries"
+		find "${ED}" -name "*.a" -and -not -name "*_nonshared.a" -delete
+	fi
+}
+
+# Simple test to make sure our new glibc isn't completely broken.
+# Make sure we don't test with statically built binaries since
+# they will fail.  Also, skip if this glibc is a cross compiler.
+#
+# If coreutils is built with USE=multicall, some of these files
+# will just be wrapper scripts, not actual ELFs we can test.
+glibc_sanity_check() {
+	cd / #228809
+
+	# We enter ${ED} so to avoid trouble if the path contains
+	# special characters; for instance if the path contains the
+	# colon character (:), then the linker will try to split it
+	# and look for the libraries in an unexpected place. This can
+	# lead to unsafe code execution if the generated prefix is
+	# within a world-writable directory.
+	# (e.g. /var/tmp/portage:${HOSTNAME})
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	local x striptest
+	for x in cal date env free ls true uname uptime ; do
+		x=$(type -p ${x})
+		[[ -z ${x} || ${x} != ${EPREFIX}/* ]] && continue
+		striptest=$(LC_ALL="C" file -L ${x} 2>/dev/null) || continue
+		case ${striptest} in
+		*"statically linked"*) continue;;
+		*"ASCII text"*) continue;;
+		esac
+		# We need to clear the locale settings as the upgrade might want
+		# incompatible locale data.  This test is not for verifying that.
+		LC_ALL=C \
+		./ld-*.so --library-path . ${x} > /dev/null \
+			|| die "simple run test (${x}) failed"
+	done
+
+	popd >/dev/null
+}
+
+pkg_preinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	# prepare /etc/ld.so.conf.d/ for files
+	mkdir -p "${EROOT}"/etc/ld.so.conf.d
+
+	# Default /etc/hosts.conf:multi to on for systems with small dbs.
+	if [[ $(wc -l < "${EROOT}"/etc/hosts) -lt 1000 ]] ; then
+		sed -i '/^multi off/s:off:on:' "${ED}"/etc/host.conf
+		einfo "Defaulting /etc/host.conf:multi to on"
+	fi
+
+	[[ -n ${ROOT} ]] && return 0
+	[[ -d ${ED}/$(get_libdir) ]] || return 0
+	[[ -z ${BOOTSTRAP_RAP} ]] && glibc_sanity_check
+}
+
+pkg_postinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	if ! tc-is-cross-compiler && [[ -x ${EROOT}/usr/sbin/iconvconfig ]] ; then
+		# Generate fastloading iconv module configuration file.
+		"${EROOT}"/usr/sbin/iconvconfig --prefix="${ROOT}/"
+	fi
+
+	if ! is_crosscompile && [[ -z ${ROOT} ]] ; then
+		use compile-locales || run_locale_gen "${EROOT}/"
+	fi
+
+	# Check for sanity of /etc/nsswitch.conf, take 2
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] && ! has_version sys-auth/libnss-nis ; then
+		local entry
+		for entry in passwd group shadow; do
+			if egrep -q "^[ \t]*${entry}:.*nis" "${EROOT}"/etc/nsswitch.conf; then
+				ewarn ""
+				ewarn "Your ${EROOT}/etc/nsswitch.conf uses NIS. Support for that has been"
+				ewarn "removed from glibc and is now provided by the package"
+				ewarn "  sys-auth/libnss-nis"
+				ewarn "Install it now to keep your NIS setup working."
+				ewarn ""
+			fi
+		done
+	fi
+}