distutils.spawn.find_executable() now falls back on os.defpath if the
PATH environment variable is not set.

(cherry picked from commit 39487196)

The change to Tools/scripts/diff.py effectively backports part of
a2637729.
The test code changed in Doc/library/difflib.rst is not present in current 3.x.

... by removing a superfluous "either".

Reported by Никита Люшненко on docs@

(cherry picked from commit 98b976a2)

Sometimes some versions of the shared libraries that are part of the
traceback are compiled in optimised mode and the Program Counter (PC)
is not present, not allowing gdb to walk the frames back. When this
happens, the Python bindings of gdb raise an exception, making the
test impossible to succeed.
(cherry picked from commit f2ef51f8)
Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>

closes bpo-34540: Convert shutil._call_external_zip to use subprocess rather than distutils.spawn. (GH-8985)

(cherry picked from commit 91cb298f)
Co-authored-by: Vladimir Matveev <v2matveev@outlook.com>

(cherry picked from commit 704e2d37)
Co-authored-by: Christian Heimes <christian@cheimes.de>

Reported by Svace static analyzer.
(cherry picked from commit 2b824b25)
Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>

Reported by Svace static analyzer.
(cherry picked from commit f6247aac)
Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>

(cherry picked from commit c33bb5d4)
Co-authored-by: Ville Skyttä <ville.skytta@iki.fi>

[2.7] bpo-34457: Python/ast.c: Add missing NULL check to alias_for_import_name(). (GH-8852) (GH-8858)

Reported by Svace static analyzer.
(cherry picked from commit 28853a24)
Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>

(cherry picked from commit 3e26e42c)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

[2.7] bpo-30411: Use --git-dir instead of -C to make git work under version below 1.8.5. (GH-8744) (GH-8838)

(cherry picked from commit 4c855577)

Read from data socket to avoid "[SSL] shutdown while in init" exception
during shutdown of the dummy server.
Signed-off-by: Christian Heimes <christian@python.org>

<!-- issue-number: [bpo-34391](https://www.bugs.python.org/issue34391) -->
https://bugs.python.org/issue34391
<!-- /issue-number -->.
(cherry picked from commit 1590c393)
Co-authored-by: Christian Heimes <christian@python.org>

Avoid undefined pointer arithmetic with NULL.
(cherry picked from commit 7c4ab2af)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Downstream vendors have started to deprecate weak keys. Update all RSA keys
and DH params to use at least 2048 bits.

Finite field DH param file use RFC 7919 values, generated with

    certtool --get-dh-params --sec-param=high

Signed-off-by: Christian Heimes <christian@python.org>.
(cherry picked from commit 88bfd0bc)
Co-authored-by: Christian Heimes <christian@python.org>

(cherry picked from commit 8f7bb100)

This was backported by mistake in ef19fd20.

The change in the mini language floating point and decimal table
is consistent with 'Exponential notation' and clarifies that we
are referring to the output notation, not an object type.

(cherry picked from commit 28c7f8c8)

(cherry picked from commit 2ebd3813)
Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

Some MacOS-tk combinations need .update_idletasks().
The call is both unneeded and innocuous on Linux and Windows.
Patch by Kevin Walzer.

(cherry picked from commit 9beaef62)
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

* Fix compilation warning in _ctypes module on Window

(cherry picked from commit 20f11fe4)

* Fix compilation warnings on Windows 64-bit

(cherry picked from commit 725e4212)

* Fix compiler warning in unicodeobject.c

Explicitly case to Py_UNICODE to fix the warning:

Objects\unicodeobject.c(4225): warning C4244: '=' :
conversion from 'long' to 'Py_UNICODE', possible loss of data

The downcast cannot overflow since we check that value <= 0x10ffff.

Use a local scope for the 'i' variable.

Fixed bpo-29565: Corrected ctypes passing of large structs by value.

Added code and test to check that when a structure passed by value
is large enough to need to be passed by reference, a copy of the
original structure is passed. The callee updates the passed-in value,
and the test verifies that the caller's copy is unchanged. A similar
change was also added to the test added for bpo-20160 (that test was
passing, but the changes should guard against regressions).

(cherry picked from commit a86339b8)

Added missing .grab_release() calls to all places where we call .grab_set().

(cherry picked from commit 10ea9409)

(cherry picked from commit c48e26dc)
Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

(cherry picked from commit 6921ef7b)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

bpo-34229: Check start and stop of slice object to be long when they are not int in PySlice_GetIndices (GH-8480)

(cherry picked from commit c0f0a766)
Co-authored-by: Aaron Ang <aaronang@users.noreply.github.com>

The script will exit with the number 0 (zero), instead of the letter O.
(cherry picked from commit 95d34c2a)
Co-authored-by: Mariatta <Mariatta@users.noreply.github.com>

(cherry picked from commit bde782bb)
Co-authored-by: Matthias Bussonnier <bussonniermatthias@gmail.com>

imaplib now allows MOVE command in IMAP4.uid() (RFC 6851:
IMAP MOVE Extension) and potentially as a name of supported
method of IMAP4 object.
(cherry picked from commit caa331d4)
Co-authored-by: Matěj Cepl <mcepl@cepl.eu>

(cherry picked from commit e271ca78)
(cherry picked from commit c75c1e0e)

There was a missing check for integer overflow, several function calls
were not checked for failure, and allocated memory was not freed if an
error occurred.

(cherry picked from commit b12112b5)