--- old/make/common/MakeBase.gmk	2017-10-05 11:56:00.476773199 +0200
+++ new/make/common/MakeBase.gmk	2017-10-05 11:56:00.216777304 +0200
@@ -991,6 +991,6 @@
 ################################################################################
 
 # Hook to include the corresponding custom file, if present.
-$(eval $(call IncludeCustomExtension, , common/MakeBase.gmk))
+$(eval $(call IncludeCustomExtension, common/MakeBase.gmk))
 
 endif # _MAKEBASE_GMK