Issue #18711: Add a new `PyErr_FormatV` function, similar to `PyErr_Format` but accepting a `va_list` argument.

remove delayed calls that were cancelled.

calls that were cancelled.

Remove pointless "vile hack" that can cause the build step to fail when some extension modules can't be imported.

See issue #5309 for the build failures, issue #458343 for the original motivation.

_read_null(), because _read_null() cannot be used on AIX. On AIX, reading from
NULL is allowed: the first page of memory is a mapped read-only on AIX.

_read_null() and _sigabrt() don't accept parameters.

because _read_null() cannot be used on AIX. On AIX, reading from NULL is
allowed: the first page of memory is a mapped read-only on AIX.

crash.

os.posix_fadvise() nor os.posix_fallocate() because their prototypes in system
headers are wrong.

os.posix_fallocate() because their prototypes in system headers are wrong.

-Wsign-compare warnings in unicodeobject.c.  These were all a result
of sizeof() being unsigned and being compared to a Py_ssize_t.
Not actual problems.

From Robert Collins.

cleanup overflowing handling in unicode_decode_call_errorhandler and unicode_encode_ucs1 (closes #22518)

limited by 100.

Patch by Claudiu Popa.

I accidentally merged this in 90b07d422bd9; this merge addresses the
last review comments on the patch.

I accidentally committed this in 6375bf34fff6; this changeset addresses the
last review comments on the patch.

This is a perennial question and something someone opens a ticket for probably
every other month or so, so I'm surprised we didn't already have a FAQ entry
for it.

The original patch was written by M. Votz, refined first by Ezio Melotti and
further refined by me.

This patch brings the pure-python datetime more in-line with the C
module.  Patch contributed by Brian Kearns, a PyPy developer.  PyPy
project has been running these modifications in PyPy2 stdlib.

This commit includes:

- General PEP8/cleanups;
- Better testing of argument types passed to constructors;
- Removal of duplicate operations;
- Optimization of timedelta creation;
- Caching the result of __hash__ like the C accelerator;
- Enhancements/bug fixes in tests.