sci-mathematics/flint: new revision to fix x86 gmp detection.

The FindGMP routine in upstream's CMake is using voodoo to determine
the version of gmp that's installed. The sorcery succeeds quite
accidentally on amd64, but fails on x86. We patch their cmake
to do something more reliable.

Bug: https://bugs.gentoo.org/771663
Package-Manager: Portage-3.0.17, Repoman-3.0.2
Signed-off-by: Michael Orlitzky <mjo@gentoo.org>

2 files changed, 154 insertions, 0 deletions

diff --git a/sci-mathematics/flint/files/flint-2.7.1-fix-cmake-findgmp.patch b/sci-mathematics/flint/files/flint-2.7.1-fix-cmake-findgmp.patch
new file mode 100644
index 000000000000..d94d65c08d7e
--- /dev/null
+++ b/sci-mathematics/flint/files/flint-2.7.1-fix-cmake-findgmp.patch
@@ -0,0 +1,152 @@
+From 9f1ef23f34a7ceca1063606cfc749e4d32bef81c Mon Sep 17 00:00:00 2001
+From: Michael Orlitzky <michael@orlitzky.com>
+Date: Mon, 19 Apr 2021 16:56:54 -0400
+Subject: [PATCH 1/1] CMake/FindGMP.cmake: compile a test program to check the
+ gmp version.
+
+The existing GMP version check consists of grepping the contents of
+the gmp.h header to parse out a few constants. This test fails, at
+least, on Gentoo, where the usual header file is a wrapper that
+includes the true header (to allow for simultaneous 32/64-bit
+support).
+
+This commit updates the FindGMP check to compile a test program
+against gmp.h that compares the version bounds within C, and reports
+success or failure as the return value from main().
+---
+ CMake/FindGMP.cmake | 97 +++++++++++++++++++++++++--------------------
+ 1 file changed, 53 insertions(+), 44 deletions(-)
+
+diff --git a/CMake/FindGMP.cmake b/CMake/FindGMP.cmake
+index ce4df70f5..bd2871ca3 100644
+--- a/CMake/FindGMP.cmake
++++ b/CMake/FindGMP.cmake
+@@ -2,28 +2,23 @@
+ # https://gmplib.org/
+ #
+ # This module supports requiring a minimum version, e.g. you can do
+-#   find_package(GMP 6.0.0)
+-# to require version 6.0.0 to newer of GMP.
++#   find_package(GMP 6.2.1)
++# to require version 6.2.1 to newer of GMP.
+ #
+ # Once done this will define
+ #
+ #  GMP_FOUND - system has GMP lib with correct version
+ #  GMP_INCLUDE_DIRS - the GMP include directory
+ #  GMP_LIBRARIES - the GMP library
+-#  GMP_VERSION - GMP version
+ #
+-# Copyright (c) 2016 Jack Poulson, <jack.poulson@gmail.com>
+-# Redistribution and use is allowed according to the terms of the BSD license.
+ 
+-find_path(GMP_INCLUDE_DIRS NAMES gmp.h PATHS $ENV{GMPDIR} ${INCLUDE_INSTALL_DIR})
+-
+-# Set GMP_FIND_VERSION to 5.1.0 if no minimum version is specified
++# Set GMP_FIND_VERSION to 6.0.0 if no minimum version is specified
+ if(NOT GMP_FIND_VERSION)
+   if(NOT GMP_FIND_VERSION_MAJOR)
+-    set(GMP_FIND_VERSION_MAJOR 5)
++    set(GMP_FIND_VERSION_MAJOR 6)
+   endif()
+   if(NOT GMP_FIND_VERSION_MINOR)
+-    set(GMP_FIND_VERSION_MINOR 1)
++    set(GMP_FIND_VERSION_MINOR 0)
+   endif()
+   if(NOT GMP_FIND_VERSION_PATCH)
+     set(GMP_FIND_VERSION_PATCH 0)
+@@ -32,43 +27,57 @@ if(NOT GMP_FIND_VERSION)
+     "${GMP_FIND_VERSION_MAJOR}.${GMP_FIND_VERSION_MINOR}.${GMP_FIND_VERSION_PATCH}")
+ endif()
+ 
+-if(GMP_INCLUDE_DIRS)
+-  # Since the GMP version macros may be in a file included by gmp.h of the form
+-  # gmp-.*[_]?.*.h (e.g., gmp-x86_64.h), we search each of them.
+-  file(GLOB GMP_HEADERS "${GMP_INCLUDE_DIRS}/gmp.h" "${GMP_INCLUDE_DIRS}/gmp-*.h"
+-	  "${GMP_INCLUDE_DIRS}/x86*/gmp.h")
+-  foreach(gmp_header_filename ${GMP_HEADERS})
+-    file(READ "${gmp_header_filename}" _gmp_version_header)
+-    string(REGEX MATCH
+-      "define[ \t]+__GNU_MP_VERSION[ \t]+([0-9]+)" _gmp_major_version_match
+-      "${_gmp_version_header}")
+-    if(_gmp_major_version_match)
+-      set(GMP_MAJOR_VERSION "${CMAKE_MATCH_1}")
+-      string(REGEX MATCH "define[ \t]+__GNU_MP_VERSION_MINOR[ \t]+([0-9]+)"
+-        _gmp_minor_version_match "${_gmp_version_header}")
+-      set(GMP_MINOR_VERSION "${CMAKE_MATCH_1}")
+-      string(REGEX MATCH "define[ \t]+__GNU_MP_VERSION_PATCHLEVEL[ \t]+([0-9]+)"
+-        _gmp_patchlevel_version_match "${_gmp_version_header}")
+-      set(GMP_PATCHLEVEL_VERSION "${CMAKE_MATCH_1}")
+-      set(GMP_VERSION
+-        ${GMP_MAJOR_VERSION}.${GMP_MINOR_VERSION}.${GMP_PATCHLEVEL_VERSION})
+-    endif()
+-  endforeach()
++find_path(GMP_INCLUDE_DIRS
++          NAMES gmp.h
++          PATHS $ENV{GMPDIR} ${INCLUDE_INSTALL_DIR})
+ 
+-  # Check whether found version exists and exceeds the minimum requirement
+-  if(NOT GMP_VERSION)
+-    set(GMP_VERSION_OK FALSE)
+-    message(STATUS "GMP version was not detected")
+-  elseif(${GMP_VERSION} VERSION_LESS ${GMP_FIND_VERSION})
+-    set(GMP_VERSION_OK FALSE)
+-    message(STATUS "GMP version ${GMP_VERSION} found in ${GMP_INCLUDE_DIRS}, "
+-                   "but at least version ${GMP_FIND_VERSION} is required")
+-  else()
+-    set(GMP_VERSION_OK TRUE)
+-  endif()
++find_library(GMP_LIBRARIES
++             gmp
++             PATHS $ENV{GMPDIR} ${LIB_INSTALL_DIR})
++
++if(GMP_INCLUDE_DIRS AND GMP_LIBRARIES)
++
++  # Return "1" if the version is OK, or "0" otherwise.  This is
++  # opposite the usual C program conventions, but makes the purpose of
++  # the result variable semantically clear. We create an integer using
++  # a few basic GMP functions to ensure that we can actually link against
++  # the GMP library.
++  file(WRITE ${PROJECT_BINARY_DIR}/gmp-version-check.c ""
++  "#include <gmp.h>\n"
++  "\n"
++  "int main(int argc, char **argv) {\n"
++  "  mpz_t x;\n"
++  "  mpz_init_set_str(x, \"7612058254738945\", 10);\n"
++  "  mpz_clear(x);\n"
++  "  if (__GNU_MP_VERSION < ${GMP_FIND_VERSION_MAJOR}) {\n"
++  "    return 0;\n"
++  "  }\n"
++  "  else {\n"
++  "    if (__GNU_MP_VERSION_MINOR < ${GMP_FIND_VERSION_MINOR}) {\n"
++  "      return 0;\n"
++  "    }\n"
++  "    else {\n"
++  "      if (__GNU_MP_VERSION_PATCHLEVEL < ${GMP_FIND_VERSION_PATCH}) {\n"
++  "        return 0;\n"
++  "      }\n"
++  "    }\n"
++  "  }\n"
++  "  return 1;\n"
++  "}\n")
++
++  # Try to run the test program above with the appropriate version
++  # strings substituted in.
++  try_run(GMP_VERSION_OK
++          GMP_VERSION_COMPILE_OK
++          "${PROJECT_BINARY_DIR}"
++          "${PROJECT_BINARY_DIR}/gmp-version-check.c"
++          CMAKE_FLAGS "-DINCLUDE_DIRECTORIES=${GMP_INCLUDE_DIRS}"
++          LINK_LIBRARIES "${GMP_LIBRARIES}")
+ endif()
+ 
+-find_library(GMP_LIBRARIES gmp PATHS $ENV{GMPDIR} ${LIB_INSTALL_DIR})
++if(NOT GMP_VERSION_OK)
++  message(STATUS "No sufficient GMP version detected")
++endif()
+ 
+ include(FindPackageHandleStandardArgs)
+ find_package_handle_standard_args(GMP DEFAULT_MSG
+-- 
+2.26.3
+
diff --git a/sci-mathematics/flint/flint-2.7.1.ebuild b/sci-mathematics/flint/flint-2.7.1-r1.ebuild
index 92eb4e95a2c2..912adc940b12 100644
--- a/sci-mathematics/flint/flint-2.7.1.ebuild
+++ b/sci-mathematics/flint/flint-2.7.1-r1.ebuild
@@ -36,6 +36,8 @@ DEPEND="dev-libs/gmp:=
 	virtual/cblas"
 RDEPEND="${DEPEND}"
 
+PATCHES=( "${FILESDIR}/${P}-fix-cmake-findgmp.patch" )
+
 src_configure() {
 	local mycmakeargs=(
 		-DWITH_NTL="$(usex ntl)"