Fix UnboundLocalError regression due to previous incorrect fix for
issue 16248.
Null merge.
Issue #18747: Re-seed OpenSSL's pseudo-random number generator after fork.
A pthread_atfork() child handler is used to seeded the PRNG with pid, time
and some stack data.
merge
Issue #15233: Python now guarantees that callables registered with the atexit
module will be called in a deterministic order.
Issue #17119: Fixed integer overflows when processing large Unicode strings
and tuples in the tkinter module.