--- Makefile.orig	2003-09-04 17:44:24.000000000 +0200
+++ Makefile	2012-11-30 13:54:33.684116105 +0100
@@ -1,8 +1,8 @@
 # $Id: Makefile,v 1.3 2003/09/04 15:44:24 varfar Exp $
 
-CC = gcc
-CFLAGS = ${OPT} ${DBG} -DSIM_STRIP_FLAGS=1
-OPT = -O4 -fomit-frame-pointer
+CC ?= gcc
+CFLAGS += ${OPT} ${DBG} -DSIM_STRIP_FLAGS=1
+OPT = -fomit-frame-pointer
 #DBG = -g -DDEBUG=2
 
 # Recommended extra options for gcc: