diff --git a/CMakeLists.txt b/CMakeLists.txt
index 405abc5e32..2bb0da725b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -80,7 +80,7 @@ if (FORCE64)
 	set(TARGET_M "-m64")
 	set(OBJ_FORMAT "elf64-x86-64")
 	set(LINKER_SCRIPT "ld_script_x86_64.xc")
-	list(APPEND CMAKE_C_FLAGS "-Wno-error=pointer-to-int-cast -Wno-error=int-to-pointer-cast")
+	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-error=pointer-to-int-cast -Wno-error=int-to-pointer-cast")
 else ()
 	set(TARGET_M "-m32")
 	set(OBJ_FORMAT "elf32-i386")