Improve handling of OOM errors in libpq making process hangling

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PQexec() hangs on OOM ×

First at 2014-11-25 13:15:10 by Heikki Linnakangas <hlinnakangas at vmware.com>
Latest at 2016-02-06 12:11:58 by Michael Paquier <michael.paquier at gmail.com>
Latest attachment (0002-Fix-OOM-error-handling-in-BIND-protocol-of-libpq.patch) at 2015-10-16 02:00:51 from Michael Paquier <michael.paquier at gmail.com>

    Attachment (0002-Fix-OOM-error-handling-in-BIND-protocol-of-libpq.patch) at 2015-10-16 02:00:51 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (0002-Fix-OOM-error-handling-in-BIND-protocol-of-libpq.patch) at 2015-10-11 13:01:38 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (0003-Remove-dead-code-of-libpq-protocol-3.patch) at 2015-09-18 22:17:46 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (0001-Initial-version-of-libpq-mallocfail-tester.patch) at 2015-09-18 17:55:38 from Heikki Linnakangas <hlinnaka at iki.fi> (Patch: Yes)
    Attachment (extended.c) at 2015-09-14 01:36:32 from Michael Paquier <michael.paquier at gmail.com> (Patch: No)
    Attachment (20150912_libpq_oom_v4.patch) at 2015-09-12 09:11:06 from Amit Kapila <amit.kapila16 at gmail.com> (Patch: Yes)
    Attachment (0002-Remove-dead-code-of-libpq-protocol-3.patch) at 2015-09-08 11:48:38 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (extended.c) at 2015-09-07 15:13:15 from Michael Paquier <michael.paquier at gmail.com> (Patch: No)
    Attachment (0002-Remove-dead-code-of-libpq-protocol-3.patch) at 2015-09-07 13:41:34 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (20150905_libpq_oom_v3.patch) at 2015-09-05 12:45:24 from Amit Kapila <amit.kapila16 at gmail.com> (Patch: Yes)
    Attachment (20150904_libpq_oom_v2.patch) at 2015-09-04 07:25:35 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (0002-Prevent-hangling-of-libpq-for-BIND-message-results-o.patch) at 2015-07-09 13:04:19 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (improve-OOM-handling-in-libpq-3.patch) at 2015-07-06 17:13:46 from Heikki Linnakangas <hlinnaka at iki.fi> (Patch: Yes)
    Attachment (improve-OOM-handling-in-libpq-2.patch) at 2015-07-03 16:32:36 from Heikki Linnakangas <hlinnaka at iki.fi> (Patch: Yes)
    Attachment (0001-Improve-OOM-detection-of-parseInput-in-libpq.patch) at 2015-05-26 07:01:26 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (0001-Improve-OOM-detection-of-parseInput-in-libpq.patch) at 2015-04-10 11:53:34 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (0001-Improve-OOM-detection-of-parseInput-in-libpq.patch) at 2015-04-08 04:27:08 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (0001-Improve-OOM-detection-of-parseInput-in-libpq.patch) at 2015-04-07 06:18:31 from Michael Paquier <michael.paquier at gmail.com> (Patch: Yes)
    Attachment (mallocfail.c) at 2014-11-25 13:15:10 from Heikki Linnakangas <hlinnakangas at vmware.com> (Patch: No)