Rebind locally the globals which can be looked up at shutdown
(to avoid the warnings seen on a buildbot)
diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py
index b59ac9f..c487180 100644
--- a/Lib/multiprocessing/util.py
+++ b/Lib/multiprocessing/util.py
@@ -188,7 +188,11 @@
 
         _finalizer_registry[self._key] = self
 
-    def __call__(self, wr=None):
+    def __call__(self, wr=None,
+                 # Need to bind these locally because the globals can have
+                 # been cleared at shutdown
+                 _finalizer_registry=_finalizer_registry,
+                 sub_debug=sub_debug):
         '''
         Run the callback unless it has already been called or cancelled
         '''