Snow Leopard doesn't like me (or the opposite?), the changeset 358a2bcd0d0b introduced a regression. I'm unable to reproduce, I ran test_socket on Linux (3.18), Mac OS X (Yosemite, Mac OS X 10.10) and FreeBSD (10).

I don't see a significant difference in sock_sendmsg() 

http://buildbot.python.org/all/builders/AMD64%20Snow%20Leop%203.x/builds/2896/steps/test/logs/stdio

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ERROR: testSendmsgTimeout (test.test_socket.SendmsgTCPTest)
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Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.x.murray-snowleopard/build/Lib/test/test_socket.py", line 266, in _tearDown
    raise exc
  File "/Users/buildbot/buildarea/3.x.murray-snowleopard/build/Lib/test/test_socket.py", line 278, in clientRun
    test_func()
  File "/Users/buildbot/buildarea/3.x.murray-snowleopard/build/Lib/test/test_socket.py", line 2224, in _testSendmsgTimeout
    self.sendmsgToServer([b"a"*512])
  File "/Users/buildbot/buildarea/3.x.murray-snowleopard/build/Lib/test/test_socket.py", line 1913, in sendmsgToServer
    *(args + self.sendmsg_to_server_defaults[len(args):]))
BrokenPipeError: [Errno 32] Broken pipe

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FAIL: testSendmsgTimeout (test.test_socket.SendmsgTCPTest)
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Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.x.murray-snowleopard/build/Lib/test/test_socket.py", line 2217, in testSendmsgTimeout
    self.assertTrue(self.misc_event.wait(timeout=self.fail_timeout))
AssertionError: False is not true