posixmodule.c 2.335.  Really should be considered part of patch #1103951.

and test_support.run_classtests() into run_unittest()
and use it wherever possible.

Also don't use "from test.test_support import ...", but
"from test import test_support" in a few spots.

From SF patch #662807.

getlogin() can fail for too many reasons, so remove the test

Don't bother testing os.getlogin() if we aren't running from a tty (terminal)
It fails when run without a tty (e.g., when run from cron).

import from test.test_support instead of directly from test_support.

Remove PyArg_ParseTuple() for methods which take no args,
use METH_NOARGS instead