diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
index faecb0da07ad..c5864af945a4 100644
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -151,7 +151,7 @@ if (LLVM_COMPILER_IS_GCC_COMPATIBLE)
 endif ()
 
 if (APPLE)
-  set(CMAKE_MODULE_LINKER_FLAGS "-Wl,-flat_namespace -Wl,-undefined -Wl,suppress")
+  set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -Wl,-flat_namespace -Wl,-undefined -Wl,suppress")
 endif ()
 
 configure_file(