Backport from Python 3.2 (e11b4c945f7e).

sys.platform is now always 'linux2' on Linux (even on Linux 3)

merge from 3.2.  Fix closes Issue11155  - Correct the multiprocessing.Queue.put's arg (replace 'item' with 'obj') in the docs. Patch by Westley Martínez.

tarfile unnecessarily checked the existence of numerical user and group ids on
extraction. If one of them did not exist the respective id of the current user
(i.e. root) was used for the file and ownership information was lost. (Patch
by Sebastien Luttringer)

sdist used to crash with a full traceback dump instead of printing a
nice warning with the faulty line number.

a string.

Backport of R. David Murray’s 3.2 patch.  The code is ugly, with print
statements split across lines, but the output is readable.

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

Patch by Hallvard B Furuseth.

some functions like file.write().

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.