Merge with 3.1.

diff --cc Doc/c-api/init.rst
index 535bf12364a0537897f34c9dfc43eb36ecbc1924,e78add1041ae8fd958871afba6ef6c2e33f8bc30..9a78834cdd379844b3da10e72bea78871e981efb
--- 1/Doc/c-api/init.rst
--- 2/Doc/c-api/init.rst
+++ b/Doc/c-api/init.rst
@@@ -489,8 -472,8 +489,8 @@@ the fork, and releasing them afterwards
  :ref:`lock-objects` in the child. When extending or embedding Python, there
  is no way to inform Python of additional (non-Python) locks that need to be
  acquired before or reset after a fork. OS facilities such as
- :c:func:`posix_atfork` would need to be used to accomplish the same thing.
 -:cfunc:`pthread_atfork` would need to be used to accomplish the same thing.
 -Additionally, when extending or embedding Python, calling :cfunc:`fork`
++:c:func:`pthread_atfork` would need to be used to accomplish the same thing.
 +Additionally, when extending or embedding Python, calling :c:func:`fork`
  directly rather than through :func:`os.fork` (and returning to or calling
  into Python) may result in a deadlock by one of Python's internal locks
  being held by a thread that is defunct after the fork.