+# Allow the package to add exceptions via a hook in cfg.mk;
+# for example, @PRAGMA_SYSTEM_HEADER@ can be permitted by
+# setting this to ' && !/PRAGMA_SYSTEM_HEADER/'.
+_makefile_at_at_check_exceptions ?=
+sc_makefile_at_at_check:
+ @perl -ne '/\@[A-Z_0-9]+\@/'$(_makefile_at_at_check_exceptions) \