--- a/unix/unix.mak
+++ b/unix/unix.mak
@@ -148,8 +148,10 @@ LIBRARY $(TF_LIBDIR): ../lib/tf/tf-help
 	install -m644 ../lib/py/tfutil.py ${DESTDIR}$(TF_LIBDIR)
 	install -m644 ../lib/py/urlwatch.py ${DESTDIR}$(TF_LIBDIR)
 
+CC_FOR_BUILD ?= cc
+
 makehelp: makehelp.c
-	$(CC) $(CFLAGS) -o makehelp makehelp.c
+	$(CC_FOR_BUILD) -o makehelp makehelp.c
 
 __always__:
 
@@ -158,7 +160,7 @@ __always__:
 	if test -d ../help; then cp ../help/tf-help ../lib/tf; fi
 
 ../lib/tf/tf-help.idx: ../lib/tf/tf-help makehelp
-	$(MAKE) -f ../unix/unix.mak CC='$(CC)' CFLAGS='$(CFLAGS)' makehelp
+	$(MAKE) -f ../unix/unix.mak CC_FOR_BUILD='$(CC_FOR_BUILD)' makehelp
 	./makehelp < ../lib/tf/tf-help > ../lib/tf/tf-help.idx
 
 MANPAGE $(MANPAGE): $(BUILDERS) tf.1.$(MANTYPE)man