Issue #26839: On Linux, os.urandom() now calls getrandom() with GRND_NONBLOCK
to fall back on reading /dev/urandom if the urandom entropy pool is not
initialized yet. Patch written by Colm Buckley.

- "See also" links to the new docs are now provided in the legacy pages
- links to setuptools documentation have been updated

(original patch by Susan Sun)

Based on patch by Xiang Zhang.

Patch by Xiang Zhang.

Original patch by Jelle Zijlstra.

If the underlying send() method indicates a partial write, such as when the
call is interrupted to handle a signal, the server would silently drop the
remaining data.

Also add deprecated support for SimpleHandler.stdout.write() doing partial
writes.

exclude_patterns in Sphinx conf.py will exclude the .rsts from the build. It
was incorrect exclude 2.x rsts in that.  This fix contributed again Jelle
Zijlstra, excludes doctests in whatsnew/2.7.rst from being exercised by using
doctests skip option.

Patch by Terry Chia and Laura Rupprecht.

Patch contributed by Jelle Zijlstra.

Patch contributed by Jelle Zijlstra.

instead of the generic ProcessTestCase class as they are posix
specific.

  Patch by Xavier de Gaye.

Patch by ingrid, Gregory Loyse and Jelle Zijlstra.

Patch by Xavier de Gaye.

The update_idletasks solution was provided by Serhiy Storchaka.

BrokenPipeError when the child process dies before .communicate()
is called in more (all?) circumstances.

Patch by Sean Rodman, test by Kaushik N.