Force pgwin32_recv into nonblock mode when called from pgstat.c.
Force pgwin32_recv into nonblock mode when called from pgstat.c.

This should get rid of the usage of pgwin32_waitforsinglesocket entirely,
and perhaps thereby remove the race condition that's evidently still
present on some versions of Windows.  The previous arrangement was a bit
unsafe anyway, since waiting at the recv() would not allow pgstat to notice
postmaster death.

tpostgres-projects/tPostgres,arcivanov/postgres-xl,greenplum-db/gpdb,50wu/gpdb,snaga/postgres-xl,adam8157/gpdb,snaga/postgres-xl,50wu/gpdb,zeroae/postgres-xl,arcivanov/postgres-xl,50wu/gpdb,ashwinstar/gpdb,yazun/postgres-xl,jmcatamney/gpdb,xinzweb/gpdb,pavanvd/postgres-xl,techdragon/Postgres-XL,kmjungersen/PostgresXL,50wu/gpdb,xinzweb/gpdb,postmind-net/postgres-xl,50wu/gpdb,ashwinstar/gpdb,lisakowen/gpdb,arcivanov/postgres-xl,ashwinstar/gpdb,kmjungersen/PostgresXL,xinzweb/gpdb,tpostgres-projects/tPostgres,greenplum-db/gpdb,ashwinstar/gpdb,zeroae/postgres-xl,greenplum-db/gpdb,oberstet/postgres-xl,kmjungersen/PostgresXL,pavanvd/postgres-xl,lisakowen/gpdb,tpostgres-projects/tPostgres,ashwinstar/gpdb,adam8157/gpdb,greenplum-db/gpdb,arcivanov/postgres-xl,Postgres-XL/Postgres-XL,kmjungersen/PostgresXL,ovr/postgres-xl,kmjungersen/PostgresXL,postmind-net/postgres-xl,greenplum-db/gpdb,postmind-net/postgres-xl,jmcatamney/gpdb,adam8157/gpdb,arcivanov/postgres-xl,yazun/postgres-xl,pavanvd/postgres-xl,xinzweb/gpdb,lisakowen/gpdb,adam8157/gpdb,jmcatamney/gpdb,xinzweb/gpdb,lisakowen/gpdb,greenplum-db/gpdb,50wu/gpdb,pavanvd/postgres-xl,snaga/postgres-xl,ashwinstar/gpdb,lisakowen/gpdb,Postgres-XL/Postgres-XL,techdragon/Postgres-XL,lisakowen/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,adam8157/gpdb,techdragon/Postgres-XL,techdragon/Postgres-XL,greenplum-db/gpdb,adam8157/gpdb,ovr/postgres-xl,Postgres-XL/Postgres-XL,postmind-net/postgres-xl,tpostgres-projects/tPostgres,greenplum-db/gpdb,zeroae/postgres-xl,arcivanov/postgres-xl,jmcatamney/gpdb,oberstet/postgres-xl,ovr/postgres-xl,snaga/postgres-xl,yazun/postgres-xl,yazun/postgres-xl,50wu/gpdb,oberstet/postgres-xl,pavanvd/postgres-xl,xinzweb/gpdb,Postgres-XL/Postgres-XL,ashwinstar/gpdb,oberstet/postgres-xl,lisakowen/gpdb,snaga/postgres-xl,zeroae/postgres-xl,xinzweb/gpdb,techdragon/Postgres-XL,ovr/postgres-xl,Postgres-XL/Postgres-XL,jmcatamney/gpdb,ovr/postgres-xl,yazun/postgres-xl,ashwinstar/gpdb,xinzweb/gpdb,adam8157/gpdb,postmind-net/postgres-xl,jmcatamney/gpdb,50wu/gpdb,tpostgres-projects/tPostgres,zeroae/postgres-xl,adam8157/gpdb,jmcatamney/gpdb,lisakowen/gpdb