Index: Makefile
--- Makefile.orig
+++ Makefile
@@ -81,7 +81,7 @@ else
 OPT = $(POPT)
 endif
 INCLUDE = -Iinclude
-CFLAGS = $(OPT) $(WARN) $(INCLUDE) $(CFLAGS.EXTRA)
+CFLAGS += $(OPT) $(WARN) $(INCLUDE) $(CFLAGS.EXTRA)
 
 all debug: glew.lib glew.bin