--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -3,7 +3,7 @@
 IF (WIN32)
     ADD_DEFINITIONS(-D_CRT_SECURE_NO_WARNINGS)
 ELSE (WIN32)
-    SET(CMAKE_CXX_FLAGS "-Wall -fno-strict-aliasing")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -fno-strict-aliasing")
 
     OPTION(APVLV_ENABLE_DEBUG "If build binary with debug information." OFF)
     IF (APVLV_ENABLE_DEBUG)