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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REL9_0_STABLE

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=770bddc1b4b59338395185966100056d90e6dcf9

Modified Files
--------------
configure                           |   25 +++++++++++++++++++++----
configure.in                        |   21 ++++++++++++++-------
src/backend/postmaster/postmaster.c |    5 +++--
src/backend/tcop/postgres.c         |    5 +++--
4 files changed, 41 insertions(+), 15 deletions(-)