diff --git a/CMakeLists.txt b/CMakeLists.txt
index a7d518f0..78055bab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,8 +67,8 @@ add_definitions(
 )
 
 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" )
 
 
 ##### source directories ########################