Allow AF_UNIX in create_server & create_connection

Reloading the warnings module duplicates filters in warnings.filters. Fixing
the issue is tricky. It was decided to simply remove the check from Python 3.5,
since the bug only impacts Python unit tests, not real applications.

The check is kept in Python 3.6 and newer.

The fields ml_name and ml_doc are of type "const char *" rather of "char *".

Based on suggestion by Eryk Sun.

The ld_so_aix script and python.exp file are created in the build directory.
Patch by Tristan Carel and Michael Haubenwallner.

unreadable directories on Windows too.

Patch by Xiang Zhang.

unreadable directories.

C API functions.

Prevents crashes in some other posixmodule.c functions

The latter function is more readable, faster and doesn't raise exceptions.

Based on patch by Xiang Zhang.

The latter function is more readable, faster and doesn't raise exceptions.

would raise ImportError

non-integer numbers.  Django tests depend on this.

non-integer numbers.  Django tests depend on this.

non-integer numbers.  Django tests depend on this.

Patch by Matthieu S.

Patch by Gareth Rees.

parse_constant doesn't get called on 'null', 'true', 'false' since 3.1/2.7.

when decode astral characters.