diff --git a/vm/Config.unix b/vm/Config.unix
index 7817a36e3b..e7b19e96e1 100644
--- a/vm/Config.unix
+++ b/vm/Config.unix
@@ -1,4 +1,4 @@
-CFLAGS = -fomit-frame-pointer
+CFLAGS += -fomit-frame-pointer
 
 EXE_SUFFIX =
 DLL_PREFIX = lib