out the location of the problem. MS_WINDOWS currently implies !HAVE_WCSFTIME,
so the addition of !defined(HAVE_WCSFTIME) is for readability.

I added some tests in 2105ab8553b7 and found no bug, but it turns out
that the doctest is not actually run.  While converting the doctest to
unittest style, I stumbled upon this bug again and this time applied the
code patch provided by Filip Gruszczyński.

Issue #13521: dict.setdefault() now does only one lookup for the given key, making it "atomic" for many purposes.
Patch by Filip Gruszczyński.

Issue #13521: dict.setdefault() now does only one lookup for the given key, making it "atomic" for many purposes.
Patch by Filip Gruszczyński.

Issue #14123: Explicitly mention that old style % string formatting has caveats but is not going away any time soon.

but is not going away any time soon.

#14081: The sep and maxsplit parameter to str.split, bytes.split, and bytearray.split may now be passed as keyword arguments.

When people find bugs in scripts such as reindent.py, msgfmt.py or
pygettext.py, we have to try to reproduce the bug manually, apply a fix
and test manually again.  The alternative is to only read the code and
trust that it works.  This test file is a way to stop that
unsatisfactory state of things and write proper unit tests instead.

These regex changes fix a number of issues for distutils on Windows:
- #6884: impossible to include a file starting with 'build'
- #9691 and #14004: sdist includes too many files
- #13193: test_filelist failures

This commit replaces the incorrect changes done in 0a94e2f807c7 and
90b30d62caf2 to fix #13193; we were too eager to fix the test failures
and I did not study the code enough before greenlighting patches.  This
time we have unit tests from the problems reported by users to be sure
we have the right fix.

Thanks to Nadeem Vawda for his help.