* bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4

* Upgrade libexpat embedded copy from version 2.2.1 to 2.2.3 to get security
  fixes.

* Update libexpat from 2.2.3 to 2.2.4. Fix copying of partial
  characters for UTF-8 input (libexpat bug 115):
  https://github.com/libexpat/libexpat/issues/115

* Define XML_POOR_ENTROPY when compiling expat

Based on patch by Philipp Hagemeister.  This fixes a regression caused by
revision f4377699fd47.

(cherry picked from commit d274b3f1)
(cherry picked from commit 6f6bc1da)

Original patch by Demian Brecht..
(cherry picked from commit a112a8ae)

Based on patches by Duane Griffin and Tim Mitchell.
(cherry picked from commit 753bca39).
(cherry picked from commit 2f7f533c)

The current regex based splitting produces a wrong result. For example::

  http://abc#@def

Web browsers parse that URL as ``http://abc/#@def``, that is, the host
is ``abc``, the path is ``/``, and the fragment is ``#@def``.
(cherry picked from commit 90e01e50)
(cherry picked from commit cc54c1c0)

* Backport Travis CI config from master

Add .travis.yml for Travis CI.

* bpo-30231: Remove skipped test_imaplib tests (#1419) (#2193)

The public cyrus.andrew.cmu.edu IMAP server (port 993) doesn't accept
TLS connection using our self-signed x509 certificate. Remove the two
tests which are already skipped.
(cherry picked from commit 7895a058)

[security][3.3] bpo-30730: Prevent environment variables injection in subprocess on Windows. (GH-2325) (#2363)

(cherry picked from commit 46b32f30)

(cherry picked from commit f5232559)

* bpo-29591: Upgrade Modules/expat to libexpat 2.2 (#2164)

* bpo-29591: Upgrade Modules/expat to libexpat 2.2

* bpo-29591: Restore Python changes on expat

* bpo-29591: Remove expat config of unsupported platforms

Remove the configuration (Modules/expat/*config.h) of unsupported
platforms:

* Amiga
* MacOS Classic on PPC32
* Open Watcom

* bpo-29591: Remove useless XML_HAS_SET_HASH_SALT

The XML_HAS_SET_HASH_SALT define of Modules/expat/expat.h became
useless since our local expat copy was upgrade to expat 2.1 (it's now
expat 2.2.0).

(cherry picked from commit 23ec4b57)

* bpo-30694: Upgrade Modules/expat/ to libexpat 2.2.1 (#2300)

New file: Modules/expat/siphash.h.
(cherry picked from commit 5ff71323)

* bpo-30726: PCbuild _elementtree: remove duplicate defines (#2348)

bpo-30726, bpo-29591: libexpat 2.2.1 of Modules/expat/ now uses
a winconfig.h configuration file which already defines:

* XML_NS
* XML_DTD
* BYTEORDER=1234
* XML_CONTEXT_BYTES=1024
* HAVE_MEMMOVE

Remove these defines from PCbuild/_elementtree.vcxproj to prevent
compiler warnings.
Co-Authored-By: Jeremy Kloth <jeremy.kloth@gmail.com>
(cherry picked from commit c8fb58bd)

* bpo-30726: Fix elementtree warnings on Windows due to expat upgrade (#2319)

* bpo-30726: Fix elementtree warnings on Windows

Caused by usage of `getenv` which should be safe. And a few integer
truncations which should also be ok.

* bpo-30726: Don't ignore libexpat warnings which haypo intends to fix upstream

(cherry picked from commit 87c65550)

CPython workflow is changing!  We're going to start using "blurb"
to manage Misc/NEWS entries:
    https://github.com/python/core-workflow
(This will be a big win for release managers, honest.)

This checkin simply populates the "Misc/NEWS.d" subdirectory tree
so that people can start putting their news entries in there.
No other changes (yet).

non-integer numbers.  Django tests depend on this.

when decode astral characters.

plural form selections in the gettext module.  The expression parser now
supports exact syntax supported by GNU gettext.

Backport of 01ddd608b85c.

rearrange methodcaller_new so that the main error case does not cause uninitialized memory usage (closes #27783)

Reported by Thomas E. Hybel

Reported by Thomas E. Hybel

Ignore the HTTP_PROXY variable when REQUEST_METHOD environment is set, which
indicates that the script is in CGI mode.

Issue #27568 Reported and patch contributed by Rémi Rampin.

This backports the fix from #16611, per discussion with the release
manager.