--- makefile.orig	2011-06-11 14:13:08.000000000 +0000
+++ makefile	2011-08-09 10:58:25.000000000 +0000
@@ -22,18 +22,9 @@
 # THIS SOFTWARE.
 # ****************************************************************/
 
-CFLAGS = -g
-CFLAGS = -O2
-CFLAGS =
-
-CC = gcc -Wall -g
-CC = cc
-CC = gcc -Wall -g -Wwrite-strings
-CC = gcc -fprofile-arcs -ftest-coverage # then gcov f1.c; cat f1.c.gcov
-CC = gcc -O4 -Wall -pedantic -fno-strict-aliasing
+CC ?= cc
 
-YACC = bison -y
-YACC = yacc
+YACC ?= yacc
 YFLAGS = -d
 
 OFILES = b.o main.o parse.o proctab.o tran.o lib.o run.o lex.o