Suggested by Terry J. Reedy in #12298.

Text adapted from the PEP.  Addition requested by Terry J. Reedy on
2011-02-23 on python-dev.

This was discussed some months ago on python-dev.  Having tons of links
to the definition of True would be annoying, contrary to links to e.g.
the nonlocal or with statements doc.

Patch by Hallvard B Furuseth.

some functions like file.write().

the C pickle implementation.

(more than 2**31 items).  Instead, in most cases, an OverflowError is raised.

greater than FD_SETSIZE.

If the version of zlib used to compile the zlib module is incompatible
with the one that is actually linked in, then calls into zlib will fail.
This can leave attributes of the z_stream uninitialized, so we must take
care to avoid segfaulting by trying to use an invalid pointer.

Fix by Richard M. Tew.

-j doesn't pass the memlimit on to child processes, so this doesn't work at
present, and even if it did, running multiple bigmem tests at once would
usually not be desirable (since you generally want to devote as much of the
available RAM as possible to each test).

The doc already points to argparse.

Initial patch by Yue Shuaijie.

- First, support.fixup_build_ext (already used to set proper
  library_dirs value under Unix shared builds) gains the ability to
  correctly set the debug attribute under Windows debug builds.

- Second, the filename for the extension module gets a _d suffix under
  debug builds.

- Third, the test code properly puts our customized build_ext object
  into an internal dictionary to make sure that the install command will
  later use our object instead of re-creating one.  That’s the downside
  of using low-level APIs in our test code: we have to manually push
  knobs and turn handles that would otherwise be handled behind the
  scenes.

Thanks to Nadeem for the testing.

Also added some tests.

(this broken -F with e.g. test_multiprocessing)

#9200: The str.is* methods now work with strings that contain non-BMP characters even in narrow Unicode builds.

Patch by Jeremy Kloth.