On POSIX-compliant systems, :func:`!multiprocessing.util.get_temp_dir` now

ignores :envvar:`TMPDIR` (and similar environment variables) if the path

length of ``AF_UNIX`` socket files exceeds the platform-specific maximum

length when using the :ref:`forkserver

<multiprocessing-start-method-forkserver>` start method. Patch by Bénédikt

Tran.