--- Makefile.orig	Fri Apr 16 15:05:58 1999
+++ Makefile	Fri Apr 16 15:06:23 1999
@@ -1,6 +1,7 @@
-CC     = gcc
-CFLAGS = -O2 -Wall
-INCDIR = -I/usr/X11R6/include/X11
+CC     ?= gcc
+CFLAGS ?= -O2
+CFLAGS += -Wall
+INCDIR = -I/usr/X11R6/include
 DESTDIR= /usr/X11R6
 LIBDIR = -L/usr/X11R6/lib
 # for linux