pgsql: Generate and include manifest in standalone libpq build on

Log Message:
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Generate and include manifest in standalone libpq build on Windows.

Hiroshi Saito

Modified Files:
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pgsql/src/interfaces/libpq:
win32.mak (r1.49 -> r1.50)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/win32.mak?r1=1.49&r2=1.50)