CMakeLists.txt         | 1 +
 json/CMakeLists.txt    | 2 +-
 udav/CMakeLists.txt    | 2 +-
 widgets/CMakeLists.txt | 4 ++--
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3364973..0c3a645 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -316,6 +316,7 @@ endif(enable-wx)
 if(enable-qt)
 	set(MGL_HAVE_QT 1)
 	FIND_PACKAGE(Qt4 4.8 REQUIRED QtCore QtGui QtNetwork QtWebKit)
+	FIND_PACKAGE(X11)
 	if(NOT QT4_FOUND)
 		message(SEND_ERROR "Couldn't find Qt4 library.")
 	endif(NOT QT4_FOUND)
diff --git a/json/CMakeLists.txt b/json/CMakeLists.txt
index 79d4716..0a53874 100644
--- a/json/CMakeLists.txt
+++ b/json/CMakeLists.txt
@@ -9,6 +9,6 @@ include_directories(${MathGL_BINARY_DIR}/json)
 qt4_wrap_ui(json_ui_src MainWindow.ui)
 qt4_wrap_cpp(json_moc_src ${json_moc_hdr} )
 add_executable(MglForJsTestBench ${json_src} ${json_moc_src} ${json_ui_src})
-target_link_libraries(MglForJsTestBench mgl-qt ${QT_LIBRARIES})
+target_link_libraries(MglForJsTestBench mgl-qt ${QT_LIBRARIES} ${X11_LIBRARIES})
 
 endif(MGL_HAVE_QT)
diff --git a/udav/CMakeLists.txt b/udav/CMakeLists.txt
index 9a9c574..a1ff2df 100644
--- a/udav/CMakeLists.txt
+++ b/udav/CMakeLists.txt
@@ -27,7 +27,7 @@ qt4_add_resources(udav_rc_src ${udav_rc} )
 qt4_wrap_cpp(udav_moc_src ${udav_moc_hdr} )
 add_executable(udav ${udav_src} ${udav_moc_src} ${udav_rc_src})
 #set_target_properties(udav PROPERTIES COMPILE_FLAGS "${CMAKE_CXX_FLAGS} -pthread")
-target_link_libraries(udav mgl-qt ${QT_LIBRARIES})
+target_link_libraries(udav mgl-qt ${QT_LIBRARIES} ${X11_LIBRARIES})
 
 if(MGL_HAVE_PTHREAD)
 	target_link_libraries(udav ${CMAKE_THREAD_LIBS_INIT})
diff --git a/widgets/CMakeLists.txt b/widgets/CMakeLists.txt
index 90ea00c..f582003 100644
--- a/widgets/CMakeLists.txt
+++ b/widgets/CMakeLists.txt
@@ -93,7 +93,7 @@ if(MGL_HAVE_QT)
 	set_target_properties(mgl-qt-static PROPERTIES CLEAN_DIRECT_OUTPUT 1)
 	set_target_properties(mgl-qt-static PROPERTIES COMPILE_FLAGS -DMGL_STATIC_DEFINE)
 	target_link_libraries(mgl-qt mgl)
-	target_link_libraries(mgl-qt ${QT_LIBRARIES})
+	target_link_libraries(mgl-qt ${QT_LIBRARIES} ${X11_LIBRARIES})
 
 	if(enable-mgl2)
 		set_target_properties(mgl-qt PROPERTIES OUTPUT_NAME "mgl2-qt")
@@ -137,7 +137,7 @@ if(MGL_HAVE_QT AND MGL_HAVE_FLTK)
 	endif(enable-mgl2)
 
 	target_link_libraries(mgl-wnd mgl)
-	target_link_libraries(mgl-wnd ${QT_LIBRARIES})
+	target_link_libraries(mgl-wnd ${QT_LIBRARIES} ${X11_LIBRARIES})
 #	target_link_libraries(mgl-wnd ${wxWidgets_LIBRARIES})
 	target_link_libraries(mgl-wnd ${FLTK_LIBRARIES})