diff --git a/makefile b/makefile
index 9ceaaad..6b9dff5 100644
--- a/makefile
+++ b/makefile
@@ -31,8 +31,8 @@ CFLAGS = -O2
 #CC = gcc -Wall -g -Wwrite-strings
 #CC = gcc -O4 -Wall -pedantic -fno-strict-aliasing
 #CC = gcc -fprofile-arcs -ftest-coverage # then gcov f1.c; cat f1.c.gcov
-HOSTCC = gcc -g -Wall -pedantic -Wcast-qual
-CC = $(HOSTCC)  # change this is cross-compiling.
+HOSTCC ?= gcc -g -Wall -pedantic -Wcast-qual
+CC ?= $(HOSTCC)  # change this is cross-compiling.
 
 # By fiat, to make our lives easier, yacc is now defined to be bison.
 # If you want something else, you're on your own.