This commit contains the implementation of PEP570: Python positional-only parameters.

* Update Grammar/Grammar with new typedarglist and varargslist

* Regenerate grammar files

* Update and regenerate AST related files

* Update code object

* Update marshal.c

* Update compiler and symtable

* Regenerate importlib files

* Update callable objects

* Implement positional-only args logic in ceval.c

* Regenerate frozen data

* Update standard library to account for positional-only args

* Add test file for positional-only args

* Update other test files to account for positional-only args

* Add News entry

* Update inspect module and related tests

We now use a pre-built libffi binary from our binaries repository, and no longer vendor the full implementation.

Deprecate using the __int__() method in implicit conversions of Python
numbers to C integers.

This test case needs "signed short" bitfields, but the
IBM XLC compiler (on AIX) does not support this.

Skip the code and test when AIX and XLC are used.

Use __xlc__ as identifier to detect the XLC compiler.

Remove ctypes callback workaround: no longer create a callback at startup.
Avoid SELinux alert on "import ctypes" and "import uuid".

Raise ValueError OverflowError in case of a negative
_length_ in a ctypes.Array subclass.  Also raise TypeError
instead of AttributeError for non-integer _length_.
Co-authored-by: Oren Milman <orenmn@gmail.com>

Fixes warnings in tests added in bpo-32117 and bpo-34603.

p.wait()

Fixed also testing the "always" warning filter.

Fix typos found by codespell in docs, docstrings, and comments.

Implement find_library() support in ctypes/util for AIX.

Add some AIX specific tests.

* Fix multiple typos in code comments

* Add spacing in comments (test_logging.py, test_math.py)

* Fix spaces at the beginning of comments in test_logging.py

bpo-31803: time.clock() and time.get_clock_info('clock') now emit a
DeprecationWarning warning.

Replace time.clock() with time.perf_counter() in tests and demos.

Remove also hasattr(time, 'monotonic') in test_time since time.monotonic()
is now always available since Python 3.5.

bpo-31311: Fix a SystemError and a crash in ctypes._CData.__setstate__(), in case of a bad __dict__. (#3254)

bpo-31490: Fix an assertion failure in ctypes in case an _anonymous_ attr is defined only outside _fields_. (#3615)

* Remove Setup.config
* Always define WITH_THREAD for compatibility.

Ctypes currently produces wrong pep3118 type codes for several types.
E.g. memoryview(ctypes.c_long()).format gives "<l" on 64-bit platforms,
but it should be "<q" instead for sizeof(c_long) == 8

The problem is that the '<>' endian specification in the struct syntax
also turns on the "standard size" mode, which makes type characters have
a platform-independent meaning, which does not match with the codes used
internally in ctypes.  The struct module format syntax also does not
allow specifying native-size non-native-endian items.

This commit adds a converter function that maps the internal ctypes
codes to appropriate struct module standard-size codes in the pep3118
format strings. The tests are modified to check for this.

Based on patch by Victor Stinner.

Add private C API function _PyUnicode_AsUnicode() which is similar to
PyUnicode_AsUnicode(), but checks for null characters.

Raise a ValueError if the second argument is NULL and the wchar_t\*
string contains null characters.

Also fixed a few more line endings that were missed in GH-840, which were causing failure.

Disable faulthandler to run test_SEH() of test_ctypes to prevent the
following log with a traceback:

    Windows fatal exception: access violation

Add support.disable_faulthandler() context manager.

* init commit, with initial tests for from_param and fields __set__ and __get__, and some additions to from_buffer and from_buffer_copy

* added the rest of tests and patches. probably only a first draft.

* removed trailing spaces

* replace ctype with ctypes in error messages

* change back from ctypes instance to ctype instance

* 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).

* Reverted unintended whitespace changes.

ctypes.CDLL instances.

Based on suggestion by Eryk Sun.

Loading Unix libraries via getattr() was disabled before ctypes was added to
Python.