Merge: #11866: Eliminate race condition in the computation of names for new threads.

diff --cc Lib/threading.py
index f7422dd9b332918b8e4e4d575042b64014d82f5f,37aa3b8ddc04111cdc255fa9cba9edeafef7c284..24cc911c203c26262099b1b51bcfc087425c00ca
--- 1/Lib/threading.py
--- 2/Lib/threading.py
+++ b/Lib/threading.py
@@@ -3,10 -3,13 +3,10 @@@
  import sys as _sys
  import _thread
  
 -try:
 -    from time import monotonic as _time
 -except ImportError:
 -    from time import time as _time
 +from time import monotonic as _time
  from traceback import format_exc as _format_exc
  from _weakrefset import WeakSet
- from itertools import islice as _islice
+ from itertools import islice as _islice, count as _count
  try:
      from _collections import deque as _deque
  except ImportError:

diff --cc Misc/NEWS
Simple merge