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.

The doc already points to argparse.

Initial patch by Yue Shuaijie.

I need to copy the xxmodule.c file in other tests, so I moved the
support code to distutils.tests.support and improved it:
- don’t skip when run from the Lib/distutils/tests directory
- use proper skip machinery instead of custom print/return/test suite
  fiddling.

I also took out the fixup_build_ext function, which is needed for tests
to pass on Unix shared builds and Windows debug builds.

Finally, I cleaned up a few things:
- don’t remove directories in tearDown when the parent class’ tearDown
  has already registered the directories for removal
- simplify restoration of sys.path
- remove a few unused names found by pyflakes.

them being inherited by other subprocesses.

This bug doesn't seem to exist on 3.2, where daemon threads are killed
before Py_Finalize() is entered.

Also added some tests.

Patch by Jeremy Kloth.

same object as reader and writer, and deemphasize it in document order.

could appear on io.BufferedRandom streams.

Even if Python is compiled on Linux 3.

Suggested by Terry J. Reedy.

The line about the test suite will still get printed for changes in
Tools for example, which aren’t covered by the test suite, but it’s not
a big deal IMO.