--- old/make/linux/makefiles/gcc.make	2012-11-12 10:52:08.328659310 -0800
+++ new/make/linux/makefiles/gcc.make	2012-11-12 10:52:08.016663231 -0800
@@ -136,7 +136,9 @@
 ACCEPTABLE_WARNINGS = -Wpointer-arith -Wconversion -Wsign-compare
 endif
 
-CFLAGS_WARN/DEFAULT = $(WARNINGS_ARE_ERRORS) $(ACCEPTABLE_WARNINGS)
+ADDITIONAL_WARNINGS = -Wunused-function
+
+CFLAGS_WARN/DEFAULT = $(WARNINGS_ARE_ERRORS) $(ACCEPTABLE_WARNINGS) $(ADDITIONAL_WARNINGS)
 # Special cases
 CFLAGS_WARN/BYFILE = $(CFLAGS_WARN/$@)$(CFLAGS_WARN/DEFAULT$(CFLAGS_WARN/$@))