Fix a reference in subinterpreters, like test_callbacks_leak() of
test_atexit.

warnoptions is a list used to pass options from the command line to
the sys module constructor. Before this change, the list was shared
by multiple interpreter which is not the expected behaviour. Each
interpreter should have their own independent mutable world.

This change duplicates the list in each interpreter. So each
interpreter owns its own list, so each interpreter can clear its own
list.

Fix regressions introduced by:

- bpo-22257: commits 1abcf670 and 6b4be195Co-Authored-By: Victor Stinner <victor.stinner@gmail.com>
Co-Authored-By: Louie Lu <git@louie.lu>

If pass a server_hostname= that fails IDNA decoding to SSLContext.wrap_socket or SSLContext.wrap_bio, then the SSLContext object had a spurious Py_DECREF called on it, eventually leading to segfaults.

* bpo-30537: use PyNumber in itertools instead of PyLong

* bpo-30537: revert changes except to islice_new

* bpo-30537: test itertools.islice and add entry to Misc/NEWS

* Update config.{guess,sub} from gnu.org.

* Fix bpo-30584

* Adding a comment mentionning the bpo and explaining what is the identifier

* Add Denis Osipov to Misc/ACKS

Clarify that `two-pass` buffer can only be dumped once, and it prints out all text sent to it during all processing, even from Clinic blocks *after* the dumping point.

Replace `datetuil` into `dateutil`

On Windows 8, 8.1 and 10 at least, the exit code is the exception
code (no bit is cleared).

to functions implemented in C that don't support this.

Also unified error messages for functions that don't take positional or keyword
arguments.

Implemented pickling for loggers.

* Simplify X.509 extension handling code

The previous implementation had grown organically over time, as OpenSSL's API evolved.

* Delete even more code

Several class attributes have been added to calendar.HTMLCalendar that allow customization of the CSS classes used in the resulting HTML. This can be done by subclasses HTMLCalendar and overwriting those class attributes (Patch by Oz Tiram).

Also weakens the 'should this be run?' regex to allow all builds when .travis.yml changes.

* bpo-30557: faulthandler now correctly filters and displays exception codes on Windows

* Adds test for non-fatal exceptions.

* Adds bpo number to comment.

Update the code example in Functions and Methods section
Remove objtype argument in MethodType

Also on the short-lived `buildbot-custom` branch.

* bpo-30538: Update count() in Functional HOWTO

* bpo-30538: Update enumerate() arguments in Functional HOWTO

Metaprogramming a list of attributes was excessive, and made the code less readable and slower.

Initially the macOS builds are allowed to fail until such time that they can be determined to be stable and not add an unacceptable amount of time to the overall Travis-passing process.

* Fix bpo-30526: Add TextIOWrapper.reconfigure()

* Apply Nick's improved wording

* Update Misc/NEWS

We get `ERROR_BAD_NETPATH` (53) on AppVeyor which is translated to
ENOENT (2).

* bpo-30544: _io._WindowsConsoleIO.write raises the wrong error when WriteConsoleW fails

* bpo-30544: _io._WindowsConsoleIO.write raises the wrong error when WriteConsoleW fails

* bpo-30052: Always regenerate cross-references

The patch for bpo-30052 changed the preferred link target
for :func:`bytes` and :func`bytearray` references to be the
respective type definitions rather than the corresponding
builtin function entries.

This patch changes the daily documentation builds to disable
the output caching in Sphinx, in order to ensure that
cross-reference changes like this one are reliably picked
up and applied automatically after merging.

Also speed up slot_sq_item.