diff --git a/vm/Config.unix b/vm/Config.unix
index 6400f4782d..73934d7f41 100644
--- a/vm/Config.unix
+++ b/vm/Config.unix
@@ -1,5 +1,5 @@
 #ifndef DEBUG
-    C_FLAGS += -fomit-frame-pointer
+    CFLAGS += -fomit-frame-pointer
 #endif
 
 EXE_SUFFIX =