diff --git a/CMakeLists.txt b/CMakeLists.txt
index 718f1a78..2828f057 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -154,8 +154,8 @@ if( NOT WITH_DEPRECATION )
 endif( )
 
 set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -include tqt.h" )
-set( CMAKE_SHARED_LINKER_FLAGS "-Wl,--no-undefined" )
-set( CMAKE_MODULE_LINKER_FLAGS "-Wl,--no-undefined" )
+set( CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,--no-undefined" )
+set( CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -Wl,--no-undefined" )
 
 
 ##### install data ##############################