diff --git a/mozilla/tools/trace-malloc/Makefile.in b/mozilla/tools/trace-malloc/Makefile.in
index 0d23485a5be..6cffb88471b 100644
--- a/mozilla/tools/trace-malloc/Makefile.in
+++ b/mozilla/tools/trace-malloc/Makefile.in
@@ -42,6 +42,8 @@ VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
+MOZILLA_INTERNAL_API = 1
+
 REQUIRES	= xpcom \
 		  string \
 		  tracemalloc \