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_4_STABLE

Details
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http://git.postgresql.org/gitweb?p=postgresql.git;a=commitdiff;h=2dffe1f8bb92abd90ee346ca474512191f520888

Modified Files
--------------
configure | 17 +++++++++++++++++
configure.in | 7 +++++++
src/backend/postmaster/postmaster.c | 5 +++--
3 files changed, 27 insertions(+), 2 deletions(-)