Ubuntu 10.10 introduced $UBUNTU_MENUPROXY into the default user environment,
and that's what's tripping up the code.

as to mark CPU-heavy tests.

where supported by the system.  Patch by Nikita Vetoshkin.

descriptor.

Improve also the comment to explain why C locale is needed to test os.environ.

#9964: fix pdb failure to import under -OO. Warn the user that help is simply not available in this case.

`done` could be released multiple times because of concurrent
execution.  We convert it to an Event, where calling set()
multiple times is not a problem.

It looks like it is no more needed: Python 3.2 is slowly able to support
non-ascii paths with an ascii locale.

Python exits with a fatal error if the command line contains an undecodable
argument. PyUnicode_FromString() fails at the first undecodable byte because it
calls the error handler, but error handlers are not ready before Python
initialization.