* bpo-30764: regrtest: change exit code on failure

* Exit code 2 if failed tests ("bad")
* Exit code 3 if interrupted

* bpo-30764: regrtest: add --fail-env-changed option

If the option is set, mark a test as failed if it alters the
environment, for example if it creates a file without removing it.

bpo-30764, bpo-29335: test_child_terminated_in_stopped_state() of
test_subprocess now uses support.SuppressCrashReport() to prevent the
creation of a core dump on FreeBSD.

* regrtest --list-cases now supports --match and --match-file options.
  Example: ./python -m test --list-cases -m FileTests test_os
* --list-cases now also sets support.verbose to False to prevent
  messages to stdout when loading test modules.
* Add support._match_test() private function.

Verify user-entered key sequences by trying to bind them with tk.
Add tests for all 3 validation functions.
Original patch by G Polo.  Tests added by Cheryl Sabella.

in `os.putenv()` and `os.spawn*()`.

* Fix bpo-30596: Add close() method to multiprocessing.Process

* Raise ValueError if close() is called before the Process is finished running

* Add docs

* Add NEWS blurb

defiend -> defined

replace `(i << 2) + 1` with `i*5`

Patch by Cheryl Sabella.

Explicitly cast on integer downcasting to fix compiler warnings.

(cherry picked from libexpat commit 788bff7a3baad1983b15b17c29e19e1a1a795c48)

Redundant code leftover from cleanup in #16191: the variable `err` is being written to, even though it wasn't used after that point.

order of keyword arguments of TestCase.subTest().

Bug didn't manifest itself when importing a module with source as .py files are always the first on the search path. The issue only showed up in bytecode-only packages where the calculated file path would be ``__init__.py/__init__.pyc``.

Patch by Alexandru Ardelean.

Prevent passing other invalid environment variables and command arguments.

Patch by Cheryl Sabella

Fix a regression introduced by myself in the commit
526b2265.

* 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

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>

Straightforward. While we're at it, though, strip trailing whitespace from generated tables.

Add "Misc/NEWS.d" directory tree for "blurb".

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).

When a class and its subclass are present, the latter is skipped.

bpo-29212: Fix the ugly ThreadPoolExecutor thread name.

Fixes the newly introduced ugly default thread name for concurrent.futures
thread.ThreadPoolExecutor threads.  They'll now resemble the old <=3.5
threading default Thread-x names by being named ThreadPoolExecutor-y_n.

bpo-30604: port fix from 3.6 dropping binary compatibility tweaks

* bpo-30183: Fixes HP-UX cc compilation error in pytime.c

HP-UX does not support the CLOCK_MONOTONIC identifier, and will fail to
compile:

    "Python/pytime.c", line 723: error #2020: identifier
    "CLOCK_MONOTONIC" is undefined
          const clockid_t clk_id = CLOCK_MONOTONIC;

Add a new section for __hpux that calls 'gethrtime()' instead of
'clock_gettime()'.

* bpo-30183: Removes unnecessary return

* bpo-30616: Functional API of enum allows to create empty enums.

* Update NEWS

move addition to avoid conflict

New file: Modules/expat/siphash.h.

Comceptually -> Conceptually