Follow-up to Victor's patch that enabled autotest to run in IDLE's Shell.
(cherry picked from commit 620f70ee)

(cherry picked from commit cd195e2a)

Pattern `[a-z]` with `IGNORECASE` flag can match to some non-ASCII characters.

Straightforward solution for this is using `IGNORECASE | ASCII` flag.
But users may subclass `Template` and override only `idpattern`. So we want to
avoid changing `Template.flags`.

So this commit uses local flag `-i` for `idpattern` and change `[a-z]` to `[a-zA-Z]`.
(cherry picked from commit b22273ec)

When regrtest in run inside IDLE, sys.stdout and sys.stderr are not
TextIOWrapper objects and have no file descriptor associated:
sys.stderr.fileno() raises io.UnsupportedOperation.

Disable faulthandler and don't replace sys.stdout in that case.
(cherry picked from commit ccef8239)

Reported by John Gamboa on docs@p.o at
https://mail.python.org/pipermail/docs/2017-June/031942.html

(cherry picked from commit 92551044)

(cherry picked from commit de072100)

(cherry picked from commit 0e61e67a)

* stdout and stderr are always opened in text mode
* and they are line-buffered

Initial patch by Gareth Rees.

* Separated functions and constants descriptions in sections.
* Added a note about the limitations of timezone constants.
* Removed redundant lists from the module docstring.

(cherry picked from commit 703ff381)

Change the code example from using `get_history_length` to `get_current_history_length`.
(cherry picked from commit eeb5ffd5)

[3.6] bpo-31728: Prevent crashes in _elementtree due to unsafe cleanup of Element.text and Element.tail (GH-3924) (#3945)

(cherry picked from commit 39ecb9c7)

Fix some tests in ./configure for determining macOS compiler choices that could fail if a $PATH element contained spaces.

(cherry picked from commit f07e2b64)

With the upgrade of buildbot.python.org from Buildbot 0.8.x to 0.9.x,
the xmlrpc interface has been removed.  This test is now skipped until
it can be rewritten to query a suitable substitute.

(cherry picked from commit 73ffd3f2)

(cherry picked from commit 79ba4714)

(cherry picked from commit 28f71360)

(cherry picked from commit 9e7b9b21)

(cherry picked from commit 2084b30e)

(cherry picked from commit a8ed1174)

Fix test_exception_errpipe_bad_data() and
test_exception_errpipe_normal() of test_subprocess: mock os.waitpid()
to avoid calling the real os.waitpid(0, 0) which is an unexpected
side effect of the test.
(cherry picked from commit 11045c9d)

(cherry picked from commit 300dd552)

* Fix incorrect links.
* Remove redundant links.
* Add signatures and index entries for gettext related
functions in the locale module.
(cherry picked from commit c02a1f4a)

when pass a string larger than 2 GiB.

Decrease memory requirements for Tcl's bigmem tests.
(cherry picked from commit 27c623c8)

(cherry picked from commit 929b40a6)

[3.6] bpo-31619: Fixed a ValueError when convert a string with large number of underscores (GH-3827) (#3863)

to integer with binary base.
(cherry picked from commit 85c0b894)

(cherry picked from commit efb560ee)

This was possible before.  GH-1560 introduced a regression after 3.6.2 got
released where only sequences were accepted now.  This commit addresses this
problem.
(cherry picked from commit 574562c5)

Use prefixed macro names for the `authoraddress` function, add T2A to the font encoding in LaTeX sources to support Cyrillic characters in the PDF documentation, and replace the deprecated `font_size` config option with `pointsize`.
(cherry picked from commit da9b4cfb)

(cherry picked from commit efb560ee)

bpo-31516: current_thread() should not return a dummy thread at shutdown
(cherry picked from commit 1023dbbc)