See PEP 11.

Broken in GH-2079

* Change NPN detection:

Version breakdown, support disabled (pre-patch/post-patch):
- pre-1.0.1: OPENSSL_NPN_NEGOTIATED will not be defined -> False/False
- 1.0.1 and 1.0.2: OPENSSL_NPN_NEGOTIATED will not be defined ->
False/False
- 1.1.0+: OPENSSL_NPN_NEGOTIATED will be defined and
OPENSSL_NO_NEXTPROTONEG will be defined -> True/False

Version breakdown support enabled (pre-patch/post-patch):
- pre-1.0.1: OPENSSL_NPN_NEGOTIATED will not be defined -> False/False
- 1.0.1 and 1.0.2: OPENSSL_NPN_NEGOTIATED will be defined and
OPENSSL_NO_NEXTPROTONEG will not be defined -> True/True
- 1.1.0+: OPENSSL_NPN_NEGOTIATED will be defined and
OPENSSL_NO_NEXTPROTONEG will not be defined -> True/True

* Refine NPN guard:

- If NPN is disabled, but ALPN is available we need our callback
- Make clinic's ssl behave the same way

This created a working ssl module for me, with NPN disabled and ALPN
enabled for OpenSSL 1.1.0f.

Concerns to address:
The initial commit for NPN support into OpenSSL [1], had the
OPENSSL_NPN_* variables defined inside the OPENSSL_NO_NEXTPROTONEG
guard. The question is if that ever made it into a release.
This would need an ugly hack, something like:

	#if defined(OPENSSL_NO_NEXTPROTONEG) && \
		!defined(OPENSSL_NPN_NEGOTIATED)
	#	define OPENSSL_NPN_UNSUPPORTED 0
	#	define OPENSSL_NPN_NEGOTIATED 1
	#	define OPENSSL_NPN_NO_OVERLAP 2
	#endif

[1] https://github.com/openssl/openssl/commit/68b33cc5c7

This comment hasn't been true since Python 3.0.

* bpo-1198569: Allow the braced pattern to be different

``string.Template`` subclasses can optionally define ``braceidpattern`` if
they want to specify different placeholder patterns inside and outside the
braces.  If None (the default) it falls back to ``idpattern``.

Blurbify master branch.

Signed-off-by: Christian Heimes <christian@python.org>

Patch by Paul.j3.  Includes an unrelated but useful addition to the
optparse porting section.

* Change code owners for hashlib and ssl to the crypto team

* Include the core CSPRNG for the crypto-team

Fix fileinput with inplace=True to accept pathlib.Path objects.

We never actually check HAVE_SELECT.

This is a required feature is C99, which we require.

Used in macOS framework builds.

Store exceptions as string rather than object to prevent reference
cycles which cause leaking dangling threads.

Call doCleanups() to close the loop after calling
executor.shutdown(wait=True): see TestCase.set_event_loop() of
asyncio.test_utils.

Replace also gc.collect() with support.gc_collect().

* bpo-31326: ProcessPoolExecutor waits for the call queue thread

concurrent.futures.ProcessPoolExecutor.shutdown() now explicitly
closes the call queue. Moreover, shutdown(wait=True) now also join
the call queue thread, to prevent leaking a dangling thread.

* Fix for shutdown() being called twice.

bpo-27144: concurrent.futures as_complete and map iterators do not keep reference to returned object (#1560)

* bpo-27144: concurrent.futures as_complie and map iterators do not keep
reference to returned object

* Some nits.  Improve wordings in docstrings and comments, and avoid relying on
sys.getrefcount() in tests.

* Explicitly call shutdown(wait=True) on executors to wait until all
  threads complete to prevent side effects between tests.
* Fix test_loop_self_reading_exception(): don't mock loop.close().
  Previously, the original close() method was called rather than the
  mock, because how set_event_loop() registered loop.close().

Use a pool of integer objects toprevent false alarm when checking for
memory block leaks. Fill the pool with values in -1000..1000 which
are the most common (reference, memory block, file descriptor)
differences.
Co-Authored-By: Antoine Pitrou <pitrou@free.fr>

Use base class rather than metaclass in examples.

Update old devguide links from https://docs.python.org/devguide to https://devguide.python.org

Code was indented with three spaces.
Fixed using four spaces.