--- Makefile	(Asterisk 15.2)
+++ Makefile	(working copy)
@@ -604 +604,2 @@
-BADMODS=$(strip $(filter-out $(shell ./build_tools/list_valid_installed_externals),$(OLDMODS)))
+-FILMODS=$(shell ./build_tools/list_valid_installed_externals)
+BADMODS=$(strip $(filter-out $(FILMODS),$(OLDMODS)))