bpo-36867: Make semaphore_tracker track other system resources (GH-13222)

The multiprocessing.resource_tracker replaces the multiprocessing.semaphore_tracker module. Other than semaphores, resource_tracker also tracks shared_memory segments. Patch by Pierre Glaser.

Lib/multiprocessing/synchronize.py

@@ -76,16 +76,16 @@ class SemLock(object):
             # We only get here if we are on Unix with forking
             # disabled.  When the object is garbage collected or the
             # process shuts down we unlink the semaphore name
-            from .semaphore_tracker import register
-            register(self._semlock.name)
+            from .resource_tracker import register
+            register(self._semlock.name, "semaphore")
             util.Finalize(self, SemLock._cleanup, (self._semlock.name,),
                           exitpriority=0)
 
     @staticmethod
     def _cleanup(name):
-        from .semaphore_tracker import unregister
+        from .resource_tracker import unregister
         sem_unlink(name)
-        unregister(name)
+        unregister(name, "semaphore")
 
     def _make_methods(self):
         self.acquire = self._semlock.acquire