* Fix _PyMem_SetupAllocators("debug"): always restore allocators to
  the defaults, rather than only caling _PyMem_SetupDebugHooks().
* Add _PyMem_SetDefaultAllocator() helper to set the "default"
  allocator.
* Add _PyMem_GetAllocatorsName(): get the name of the allocators
* main() now uses debug hooks on memory allocators if Py_DEBUG is
  defined, rather than calling directly malloc()
* Document default memory allocators in C API documentation
* _Py_InitializeCore() now fails with a fatal user error if
  PYTHONMALLOC value is an unknown memory allocator, instead of
  failing with a fatal internal error.
* Add new tests on the PYTHONMALLOC environment variable
* Add support.with_pymalloc()
* Add the _testcapi.WITH_PYMALLOC constant and expose it as
   support.with_pymalloc().
* sysconfig.get_config_var('WITH_PYMALLOC') doesn't work on Windows, so
   replace it with support.with_pymalloc().
* pythoninfo: add _testcapi collector for pymem

Remove the test.support.requires_android_level decorator.

characters/bytes for non-negative n.  This makes it compatible with
read() methods of other file-like objects.

``uuid.getnode()`` now preferentially returns universally administered MAC addresses if available, over locally administered MAC addresses.  This makes a better guarantee for global uniqueness of UUIDs returned from ``uuid.uuid1()``.  If only locally administered MAC addresses are available, the first such one found is returned.

Also improve internal code style by being explicit about ``return None`` rather than falling off the end of the function.

Improve the test robustness.

Revert distutils changes of the commit
696b501c and remove the realm
variable.

CPython migrated from CVS to Subversion, to Mercurial, and then to
Git. CVS and Subversion are not more used to develop CPython.

* platform module: drop support for sys.subversion. The
  sys.subversion attribute has been removed in Python 3.3.
* Remove Misc/svnmap.txt
* Remove Tools/scripts/svneol.py
* Remove Tools/scripts/treesync.py

* bpo-32071: Fix an undocumented behaviour regression

* bpo-32071: Add 3.7 release note entry for unittest -k

* distutils.config: Use the PyPIRCCommand.realm attribute if set
* turtledemo: wait until macOS osascript command completes to not
  create a zombie process
* Tools/scripts/treesync.py: declare 'default_answer' and
  'create_files' as globals to modify them with the command line
  arguments. Previously, -y, -n, -f and -a options had no effect.

flake8 warning: "F841 local variable 'p' is assigned to but never
used".

* Remove asyncio.selectors and asyncio._overlapped symbols from the
  namespace of the asyncio module
* Replace "from asyncio import selectors" with "import selectors"
* Replace "from asyncio import _overlapped" with "import _overlapped"

asyncio.selectors was added to support Python 3.3, which doesn't have
selectors in its standard library, and Python 3.4 in the same code
base. Same rationale for asyncio._overlapped. Python 3.3 reached its
end of life, and asyncio is no more maintained as a third party
module on PyPI.

The asyncio/compat.py file was written to support Python < 3.5 and
Python < 3.5.2. But Python 3.5 doesn't accept bugfixes anymore, only
security fixes. There is no more need to backport bugfixes to Python
3.5, and so no need to have a single code base for Python 3.5, 3.6
and 3.7.

Say hello (again) to "async" and "await", who became real keywords in
Python 3.7 ;-)

Since Python 3.5, socket.socketpair() is also available on Windows,
and so can be used directly, rather than using
asyncio.windows_utils.socketpair().

Currently, two tests fail with PYTHONASYNCIODEBUG=1 (or using -X
dev).

It was only used on Python 3.3, now only Future._log_traceback is
used.

This reverts commit 9522a218.

Some parts of the C API are only relevant to larger
applications embedding CPython as a runtime engine.

The helpers to test those APIs are already separated
out into Programs/_testembed.c, this update moves
the associated test cases out into their own dedicated
test file.

Revert "bpo-30487: automatically create a venv and install Sphinx when running make (GH-4346)" (#4592)

Fix breakage documented in bpo-32149.
This reverts commit d8d6b912.

Improve UUID1 MAC address calculation and related tests.

There are two bits in the MAC address that are relevant to UUID1.  The first is the locally administered vs. universally administered bit (second least significant of the first octet).   Physical network interfaces such as ethernet ports and wireless adapters will always be universally administered, but some interfaces --such as the interface that MacBook Pros communicate with their Touch Bars-- are locally administered.  The former are guaranteed to be globally unique, while the latter are demonstrably *not* globally unique and are in fact the same on every MBP with a Touch Bar.  With this bit is set, the MAC is locally administered; with it unset it is universally administered.

The other bit is the multicast bit (least significant bit of the first octet).  When no other MAC address can be found, RFC 4122 mandates that a random 48-bit number be generated.  This randomly generated number *must* have the multicast bit set.

The improvements in uuid.py include:

* Preferentially return a universally administered MAC address, falling back to a locally administered address if none of the former can be found.
* Improve several coding style issues, such as adding explicit returns of None, using a more readable bitmask pattern, and assuming that the ultimate fallback, random MAC generation will not fail (and propagating any exception there instead of swallowing them).

Improvements in test_uuid.py include:

* Always testing the calculated MAC for universal administration, unless explicitly disabled (i.e. for the random case), or implicitly disabled due to running in the Travis environment.  Travis test machines have *no* universally administered MAC address at the time of this writing.

The warnings module doesn't leak memory anymore in the hidden
warnings registry for the "ignore" action of warnings filters.

The warn_explicit() function doesn't add the warning key to the
registry anymore for the "ignore" action.

In development and debug mode, use the "default" action, rather than
the "always" action, for ResourceWarning in the default warnings
filters.

Wildcard is now supported in hostname when it is one and only character in
the leftmost segment.

- Add "version added: 3.5.2" note where it was missing.
- Remove the mention that Reversible is new in 3.5.2 

find_file() returns an empty list if it finds the requested
header on the standard include path, so header existence
checks need to be explicitly against "is not None".

clang can't figure out that fatal_error is noreturn itself and emits warnings:

../cpython/Python/pylifecycle.c:2116:1: warning: function declared 'noreturn' should not return [-Winvalid-noreturn]
}
^
../cpython/Python/pylifecycle.c:2125:1: warning: function declared 'noreturn' should not return [-Winvalid-noreturn]
}
^