Fix DeprecationWarning when tests are run using python -3.

The pthread implementation of PyThread_start_new_thread() now uses
malloc/free rather than PyMem_Malloc/PyMem_Free, since the latters
are not thread-safe.

Fix an undefined behaviour in the pthread implementation of
PyThread_start_new_thread(): add a function wrapper to always return
NULL.

Add pythread_callback struct and pythread_wrapper() to thread_pthread.h.

(cherry picked from commit 9eea6eaf)

testAccept() and testRecv() of test_socket.NonBlockingTCPTests have a
race condition: time.sleep() is used as a weak synchronization
primitive and the tests fail randomly on slow buildbots.

Use a reliable threading.Event to fix these tests.

Other changes:

* Replace send() with sendall()
* Add a timeout to select() in testAccept() and testRecv()
* Use addCleanup() to close sockets
* Use assertRaises()

(cherry picked from commit ebd5d6d6)

Running test_bytes with python -3 -Wd emits two DeprecationWarning on
"1/0". Use "1//0" to prevent the warning.

(cherry picked from commit a2e3585e)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

On Windows, test_env_changed() of test_regrtest is now skipped
because it fails  randomly for an unknown reason on "x86 Windows XP
VS9.0 2.7" buildbot worker.

Co-Authored-By: Pablo Galindo <Pablogsal@gmail.com>

Log TZ to debug a timezone issue... and a few more :-)

(cherry picked from commit 282c03d4)

(cherry picked from commit ba57963a)
Co-authored-by: takey <taketakeyyy@gmail.com>

https://bugs.python.org/issue35035

(cherry picked from commit 6b73bb52)
Co-authored-by: Julien Palard <julien@palard.fr>

Fixes assertion failures in _datetimemodule.c
introduced in the previous fix (see bpo-31752).

Rather of trying to handle an int subclass as exact int,
let it to use overridden special methods, but check the
result of divmod().
(cherry picked from commit 3ec0f495)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit 8b9c33ea)
Co-authored-by: Donald Stufft <donald@stufft.io>

This missed PyErr_NoMemory() could cause a SystemError when calling
_symtable.symtable().
(cherry picked from commit ad65f155)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

"single" needs to be decrefed if PyList_Append() fails.
(cherry picked from commit 4c596d54)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Discovered using clang's MemorySanitizer.

A msan build will fail by simply executing: ./python -c 'u"\N"'
(cherry picked from commit 746b2d35)

Co-authored-by: Gregory P. Smith <greg@krypto.org> [Google LLC]

(cherry picked from commit 8e0b05e2)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 9404e773)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

https://bugs.python.org/issue33699
(cherry picked from commit b086c8af)



https://bugs.python.org/issue33699

This typo doesn't affect the result because wrong bits are discarded
on implicit conversion to unsigned char, but it trips UBSan
with -fsanitize=implicit-integer-truncation.
(cherry picked from commit 7a69cf47)
Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>

(cherry picked from commit cdb96f45)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit ae31e3fb)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit c5eec442)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit d6499103)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

The test depended on '/usr/share/zoneinfo/posixrules' or equivalent
because it set TZ without explicit DST transition rules. At least
on OpenSUSE Tumbleweed that file is linked to '/etc/localtime',
making the test fail with certain local timezones,
such as 'Europe/Moscow' which doesn't have DST transitions since 2011.
(cherry picked from commit f1b9ad3d)
Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>

[2.7] bpo-35133: Fix mistakes when concatenate string literals on different lines. (GH-10284) (GH-10335) (GH-10336)

Two kind of mistakes:

1. Missed space. After concatenating there is no space between words.

2. Missed comma. Causes unintentional concatenating in a list of strings.
(cherry picked from commit 34fd4c20)
(cherry picked from commit 7054e5c80b6e98cd44e22d1bc2d7f0a94343089d)

(cherry picked from commit fe62d877)
Co-authored-by: İsmail Arılık <arilik.ismail@gmail.com>

[2.7] closes bpo-35139: The `pyexpat` module's macros in `Modules/Setup` now match `setup.py` (GH-10293)

This could cause compile errors on macOS or other platforms..
(cherry picked from commit 318ab63c)
Co-authored-by: Max Bélanger <aeromax@gmail.com>

_io.IncrementalNewlineDecoder's initializer possibly assigns out-of-range
value to the bitwise struct field.
(cherry picked from commit b08746bf)
Co-authored-by: Xiang Zhang <angwerzx@126.com>

Adding `max_num_fields` to `cgi.FieldStorage` to make DOS attacks harder by
limiting the number of `MiniFieldStorage` objects created by `FieldStorage`.

(cherry picked from commit 20914483)

(cherry picked from commit 53835e92)

(cherry picked from commit c0799ec9)
Co-authored-by: Gus Goulart <augusto@goulart.me>

(cherry picked from commit 18d57b4d)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Based on the investigation by Xiang Zhang.
(cherry picked from commit df13df41)