Issue #18571: Implementation of the PEP 446: file descriptors and file handles

are now created non-inheritable; add functions os.get/set_inheritable(),
os.get/set_handle_inheritable() and socket.socket.get/set_inheritable().

Lib/multiprocessing/semaphore_tracker.py

@@ -45,7 +45,7 @@ def ensure_running():
         except Exception:
             pass
         cmd = 'from multiprocessing.semaphore_tracker import main; main(%d)'
-        r, w = util.pipe()
+        r, w = os.pipe()
         try:
             fds_to_pass.append(r)
             # process will out live us, so no need to wait on pid