$OpenBSD: patch-Makefile,v 1.7 2015/05/06 08:47:14 ajacoutot Exp $
--- Makefile.orig	Sat Jan 24 07:45:52 2015
+++ Makefile	Mon Apr 27 00:06:34 2015
@@ -76,7 +76,7 @@ else
 OPT = $(POPT)
 endif
 INCLUDE = -Iinclude
-CFLAGS = $(OPT) $(WARN) $(INCLUDE) $(CFLAGS.EXTRA)
+CFLAGS += $(OPT) $(WARN) $(INCLUDE) $(CFLAGS.EXTRA)
 
 all debug: glew.lib glew.lib.mx glew.bin
 
