Warn when new modules are found that use user tags - DO NOT MERGE

Change-Id: Ia563765f3d0161d7c851a0162d65c2a249b4dd38
diff --git a/core/definitions.mk b/core/definitions.mk
index f42c2a3..6f7a05b 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1797,6 +1797,9 @@
 # when requested.
 include $(BUILD_SYSTEM)/distdir.mk
 
+# -----------------------------------------------------------------
+# The modules allowed to use a user tag
+include $(BUILD_SYSTEM)/user_tags.mk
 
 # broken:
 #	$(foreach file,$^,$(if $(findstring,.a,$(suffix $file)),-l$(file),$(file)))