diff --git a/layout/inspector/src/Makefile.in b/layout/inspector/src/Makefile.in
index 9e322736c9ce..4b832786397a 100644
--- a/layout/inspector/src/Makefile.in
+++ b/layout/inspector/src/Makefile.in
@@ -44,6 +44,8 @@ include $(DEPTH)/config/autoconf.mk
 
 MODULE=inspector
 LIBRARY_NAME=inspector_s
+MOZILLA_INTERNAL_API = 1
+
 REQUIRES	= xpcom \
 		  string \
 		  dom \
diff --git a/toolkit/system/Makefile.in b/toolkit/system/Makefile.in
index 85adcd4ab425..55d03da5e645 100644
--- a/toolkit/system/Makefile.in
+++ b/toolkit/system/Makefile.in
@@ -43,6 +43,7 @@ VPATH	  = @srcdir@
 include $(DEPTH)/config/autoconf.mk
 
 MODULE		= mozgnome
+MOZILLA_INTERNAL_API = 1
 
 XPIDLSRCS = \
 	nsIGConfService.idl \