Propagate to parent scope changes made to CMAKE_CXX_FLAGS.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122692 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/cmake/modules/LLVMProcessSources.cmake b/cmake/modules/LLVMProcessSources.cmake
index d9c14fb..092c2f7 100644
--- a/cmake/modules/LLVMProcessSources.cmake
+++ b/cmake/modules/LLVMProcessSources.cmake
@@ -54,6 +54,7 @@
     endif()
   endif()
 
+  set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}" PARENT_SCOPE )
   set( ${OUT_VAR} ${sources} PARENT_SCOPE )
 endfunction(llvm_process_sources)