--- Makefile.orig	2002-07-27 07:22:10.000000000 +0900
+++ Makefile	2007-12-06 16:41:35.000000000 +0900
@@ -12,8 +12,8 @@
 
 # UNIX specific definitions (default)
 #
-CC= cc
-CFLAGS= -O -DANSI_C $(LXFLAGS)
+CC?= cc
+CFLAGS+= -DANSI_C $(LXFLAGS)
 CLIB= -lm
 
 # Windows 'nmake' specific definitions