pgsql: Fix up getopt() reset management so it works on recent mingw.

Fix up getopt() reset management so it works on recent mingw.

The mingw people don't appear to care about compatibility with non-GNU
versions of getopt, so force use of our own copy of getopt on Windows.
Also, ensure that we make use of optreset when using our own copy.

Per report from Andrew Dunstan.  Back-patch to all versions supported
on Windows.

Branch
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REL8_2_STABLE

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=6a61d58ca8d28b1d0e49a6906ac61ab86f12493c

Modified Files
--------------
configure                           |   21 +++++++++++++++++++++
configure.in                        |    7 +++++++
src/backend/postmaster/postmaster.c |    5 +++--
3 files changed, 31 insertions(+), 2 deletions(-)