diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ccf531a75..5ad91e0fc 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,9 +1,9 @@
 
-set(CMAKE_C_FLAGS "-Wall ${CMAKE_C_FLAGS}")
-set(CMAKE_CXX_FLAGS "-Woverloaded-virtual -Wall -Wno-sign-compare ${CMAKE_CXX_FLAGS}")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Woverloaded-virtual -Wall -Wno-sign-compare")
 
 if (LINUX)
-  set(CMAKE_CXX_FLAGS "-Werror ${CMAKE_CXX_FLAGS}")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
 endif (LINUX)
 
 include_directories(${CMAKE_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})