--- Makefile.orig	Sat Jan 22 14:47:22 2000
+++ Makefile	Sat Jan 22 14:47:33 2000
@@ -4,7 +4,7 @@
 #
 
 # Default C compiler: must be an ANSI C compiler
-CC         = cc
+CC         ?= cc
 # File names for the main source files
 DRIV_SRC   = netpipe.c
 DRIV_OBJ   = netpipe.o
@@ -13,7 +13,7 @@
 TARGETS    = NPtcp
 # If you have TCP, MPI and PVM
 #TARGETS    = NPtcp NPmpi NPpvm
-CFLAGS	   = -O
+CFLAGS	   ?= -O
 # Adjust these for MPI (only used if you have MPI)
 MPI_HOME   = /home/mpich
 MPI_ARCH   = IRIX