Teach MSVC build system about postgres_fdw.
Teach MSVC build system about postgres_fdw.

Per buildfarm.

pavanvd/postgres-xl,Postgres-XL/Postgres-XL,xinzweb/gpdb,50wu/gpdb,xinzweb/gpdb,greenplum-db/gpdb,pavanvd/postgres-xl,ashwinstar/gpdb,lisakowen/gpdb,ashwinstar/gpdb,yazun/postgres-xl,greenplum-db/gpdb,lisakowen/gpdb,oberstet/postgres-xl,zeroae/postgres-xl,jmcatamney/gpdb,zeroae/postgres-xl,xinzweb/gpdb,adam8157/gpdb,techdragon/Postgres-XL,adam8157/gpdb,lisakowen/gpdb,adam8157/gpdb,jmcatamney/gpdb,lisakowen/gpdb,oberstet/postgres-xl,50wu/gpdb,jmcatamney/gpdb,adam8157/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,ovr/postgres-xl,oberstet/postgres-xl,oberstet/postgres-xl,greenplum-db/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,adam8157/gpdb,adam8157/gpdb,zeroae/postgres-xl,ovr/postgres-xl,greenplum-db/gpdb,techdragon/Postgres-XL,lisakowen/gpdb,oberstet/postgres-xl,yazun/postgres-xl,yazun/postgres-xl,pavanvd/postgres-xl,greenplum-db/gpdb,Postgres-XL/Postgres-XL,adam8157/gpdb,yazun/postgres-xl,greenplum-db/gpdb,50wu/gpdb,xinzweb/gpdb,ashwinstar/gpdb,xinzweb/gpdb,50wu/gpdb,ovr/postgres-xl,ashwinstar/gpdb,jmcatamney/gpdb,50wu/gpdb,pavanvd/postgres-xl,Postgres-XL/Postgres-XL,xinzweb/gpdb,jmcatamney/gpdb,pavanvd/postgres-xl,greenplum-db/gpdb,zeroae/postgres-xl,ovr/postgres-xl,xinzweb/gpdb,Postgres-XL/Postgres-XL,ashwinstar/gpdb,lisakowen/gpdb,Postgres-XL/Postgres-XL,techdragon/Postgres-XL,jmcatamney/gpdb,50wu/gpdb,50wu/gpdb,lisakowen/gpdb,techdragon/Postgres-XL,zeroae/postgres-xl,jmcatamney/gpdb,yazun/postgres-xl,xinzweb/gpdb,ovr/postgres-xl,50wu/gpdb,techdragon/Postgres-XL,ashwinstar/gpdb,adam8157/gpdb,lisakowen/gpdb