On HP-UX with C or POSIX locale, sys.getfilesystemencoding() now returns
"ascii" instead of "roman8" (when the UTF-8 Mode is disabled and the C locale
is not coerced).

nl_langinfo(CODESET) announces "roman8" whereas it uses the Latin1
encoding in practice.

* The UTF-8 Mode is now also enabled by the "POSIX" locale, not only
  by the "C" locale.
* On FreeBSD, Py_DecodeLocale() and Py_EncodeLocale() now also forces
  the ASCII encoding if the LC_CTYPE locale is "POSIX", not only if
  the LC_CTYPE locale is "C".
* test_utf8_mode.test_cmd_line() checks also that the command line
  arguments are decoded from UTF-8 when the the UTF-8 Mode is enabled
  with POSIX locale or C locale.

Robust caching of calculated properties is
harder than it looks at first glance, so add
a solid, well-tested implementation to the
standard library.

AIX uses ISO-8859-1 encoding for the C locale.

Remove "trace.cover" left from previous test runs before testing
that it is no longer created.

bpo-32968: Make modulo and floor division involving Fraction and float consistent with other operations (#5956)

Make mixed-type `%` and `//` operations involving `Fraction` and `float` objects behave like all other mixed-type arithmetic operations: first the `Fraction` object is converted to a `float`, then the `float` operation is performed as normal. This fixes some surprising corner cases, like `Fraction('1/3') % inf` giving a NaN.

Thanks Elias Zamaria for the patch.

An old apparent AIX behavior workaround in test_subprocess's
test_undecodable_env is no longer needed.

Reported by Svace static analyzer.

Reported by Svace static analyzer.

Previously marks stack was upsized even there was space for additional item.

`yield conn`, instead of just `yield`.

Avoids an integer underflow in the time module's year handling code.

bpo-34492: Python/coreconfig.c: Add missing NULL check to _Py_wstrlist_copy().

Fix _Py_wstrlist_clear() call on a wrong list.

Reported by Svace static analyzer.

Reported by Svace static analyzer.

Also, propagate the error from PyNumber_AsSsize_t() because we don't care
only about OverflowError which is not reported if the second argument is NULL.

Reported by Svace static analyzer.

Reported by Svace static analyzer.

Reported by Svace static analyzer.

There was a missing comma.

semapthores -> semaphores

The current C implementations **crash** if the input includes a surrogate
Unicode code point, which is not possible to encode in UTF-8.

Important notes:

1.  It is possible to pass a non-UTF-8 string as a separator to the
    `.isoformat()` methods.
2.  The pure-Python `datetime.fromisoformat()` implementation accepts
    strings with a surrogate as the separator.

In `datetime.fromisoformat()`, in the special case of non-UTF-8 separators,
this implementation will take a performance hit by making a copy of the
input string and replacing the separator with 'T'.
Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>
Co-authored-by: Paul Ganssle <paul@ganssle.io>

Introduce a configure check for strsignal(3) which defines HAVE_STRSIGNAL for
signalmodule.c. Add some common signals on HP-UX. This change applies for
Windows and HP-UX.

bpo-34170, bpo-34207: pymain_read_conf() now sets Py_UTF8Mode to
config->utf8_mode. pymain_read_conf() calls indirectly
Py_DecodeLocale() and Py_EncodeLocale() which depend on Py_UTF8Mode.

Reported by Svace static analyzer.