(cherry picked from commit d79c1d4)

PyNumber_Int() creates a new reference: need to decrement result
reference counter.

Add a test to check the current MAGIC_NUMBER against the
expected number for the release if the current release is
at candidate or final level. On test failure, describe to
the developer the procedure for changing the magic number.

This ensures that pre-merge CI will automatically pick up
on magic number changes in maintenance releases (and
explain why those are problematic), rather than relying on
all core developers to be aware of the implications of
such changes.

…2159) (#2168)

* bpo-24484: Avoid race condition in multiprocessing cleanup

The finalizer registry can be mutated while inspected by multiprocessing
at process exit.

* Use test.support.start_threads()

* Add Misc/NEWS.
(cherry picked from commit 1eb6c00)

Replace platform with platforms.
(cherry picked from commit 4ebf03d)

* 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 23ec4b5)

regrtest now warms up caches: create explicitly all internal
singletons which are created on demand to prevent false positives
when checking for reference leaks.

… (#2294)

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 90e01e5)

* bpo-30368: Update build_ssl.py to restore Perl-less building

OpenSSL 1.0.2 releases changed how files are copied in the makefile,
thus causing Perl to be required even for Python's "prepared" OpenSSL.
Now build_ssl.py does the requisite copies before running nmake.

* bpo-30368: Update build_ssl.py to use prepared OpenSSL

* Updates SSL-linking projects to use the new include{suffix} directory
* build_ssl.py now only copies those files not handled by prepare_ssl.py

* * bpo-30368: Update build_ssl.py to use prepared OpenSSL

* Update SSL-linking projects to use the new include{suffix} directory

* Move comment to following line

)

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

New file: Modules/expat/siphash.h.
(cherry picked from commit 5ff7132)

* siphash.h: Address lack of stdint.h for Visual Studio 2003-2008

(cherry picked from libexpat commit c74d380b8f0b5215153d840d2af9455d9c53b960)

* Silence warnings caused by duplicated defines from Modules\expat\winconfig.h
* Add WIN32 define to VS9.0 project files to match MSBuild project files.

…2320)

delaying the main thread so that it doesn't race ahead of the workers.

(cherry picked from commit 020af2a)

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).

…s on Windows. (GH-2325) (#2372)

Prevent passing other invalid environment variables and command arguments..
(cherry picked from commit d174d24)

… names (GH-2382) (#2393)

in `os.putenv()` and `os.spawn*()`..
(cherry picked from commit 7770394)

… not to (GH-2403) (#2420)

* [2.7] bpo-30765: Avoid blocking when PyThread_acquire_lock() is asked not to (GH-2403)

* bpo-30765: Avoid blocking when PyThread_acquire_lock() is asked not to lock

This is especially important if PyThread_acquire_lock() is called reentrantly
(for example from a signal handler).

* Update 2017-06-26-14-29-50.bpo-30765.Q5iBmf.rst

* Avoid core logic when taking the mutex failed.
(cherry picked from commit f84ac42)

* Remove test undef

)

* bpo-30764: Backport support.SuppressCrashReport

Backport test.support.SuppressCrashReport context-manager from
master. Drop the Windows implementation since it depends on
msvcrt.CrtSetReportMode() which isn't available on Python 2.7.

* bpo-30764: test_subprocess uses SuppressCrashReport (#2405)

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.
(cherry picked from commit cdee3f1)