--- Makefile.orig	2005-12-23 01:13:06.000000000 +0900
+++ Makefile	2007-12-11 11:35:36.000000000 +0900
@@ -19,7 +19,7 @@
 
 # set compiler for the non-MPI version (mpicc will be used for the MPI
 # version regardless of this setting)
-CC = gcc
+CC ?= gcc
 
 # set to yes if you want to use the readline library (make sure you have it
 # installed on your machine)