Thanks to os.environ under Windows only updating the dict and not the
environment itself (as exposed by nt.environ), tests using
PYTHONCASEOK always fail. Now the tests are skipped when os.environ
does not do what is expected.

On Windows, localtime(-1) fails, but not gmtime(1).

Clang 3.0 removes "y = *x;" instruction if the optimisation level is 3.

Patch by Hynek Schlawack.

Patch by Hynek Schlawack.

Issue #13806: The size check in audioop decompression functions was too strict and could reject valid compressed data.
Patch by Oleg Plakhotnyuk.

Issue #13806: The size check in audioop decompression functions was too strict and could reject valid compressed data.
Patch by Oleg Plakhotnyuk.

by Matt Joiner.

by Matt Joiner.

Issue #13889: Add missing _Py_SET_53BIT_PRECISION_* calls around uses of dtoa.c functions in float round.

Issue #13812: When a multiprocessing Process child raises an exception, flush stderr after printing the exception traceback.

Issue #13812: When a multiprocessing Process child raises an exception, flush stderr after printing the exception traceback.

This required updating the code to use posix instead of os. This is
all being done to make bootstrapping easier to removing dependencies
that are kept in importlib.__init__ and thus outside of the single
file to bootstrap from.

Skip the test if we are unable to find an invalid time_t value.