Merged revisions 78777,78787,78790 via svnmerge from

Merged revisions 78777,78787,78790 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r78777 | florent.xicluna | 2010-03-08 00:49:03 +0100 (lun, 08 mar 2010) | 4 lines

  Backport the Popen.poll() protection from subprocess to multiprocessing. See #1731717.
  It should fix transient failures on test_multiprocessing.
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  r78787 | florent.xicluna | 2010-03-08 08:21:16 +0100 (lun, 08 mar 2010) | 2 lines

  Don't fail on a debug() statement, if the worker PID is (still) None.
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  r78790 | florent.xicluna | 2010-03-08 12:01:39 +0100 (lun, 08 mar 2010) | 2 lines

  On finalize, don't try to join not started process.
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