pgsql-server: Add Win32 service capability to pg_autovacuum.

Log Message:
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Add Win32 service capability to pg_autovacuum.

Dave Page

Modified Files:
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pgsql-server/contrib/pg_autovacuum:
pg_autovacuum.c (r1.19 -> r1.20)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/contrib/pg_autovacuum/pg_autovacuum.c.diff?r1=1.19&r2=1.20)
pg_autovacuum.h (r1.10 -> r1.11)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/contrib/pg_autovacuum/pg_autovacuum.h.diff?r1=1.10&r2=1.11)