Include pxfwritable_export as part of PXF extension definiton (#3825)
Include pxfwritable_export as part of PXF extension definiton (#3825)


ashwinstar/gpdb,Chibin/gpdb,jmcatamney/gpdb,lisakowen/gpdb,edespino/gpdb,50wu/gpdb,Chibin/gpdb,xinzweb/gpdb,adam8157/gpdb,50wu/gpdb,edespino/gpdb,lisakowen/gpdb,Chibin/gpdb,50wu/gpdb,lisakowen/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,Chibin/gpdb,xinzweb/gpdb,edespino/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,Chibin/gpdb,adam8157/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,50wu/gpdb,edespino/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,50wu/gpdb,ashwinstar/gpdb,edespino/gpdb,50wu/gpdb,xinzweb/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,adam8157/gpdb,greenplum-db/gpdb,adam8157/gpdb,xinzweb/gpdb,lisakowen/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,lisakowen/gpdb,edespino/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,xinzweb/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,lisakowen/gpdb,adam8157/gpdb,Chibin/gpdb,adam8157/gpdb,yuanzhao/gpdb,adam8157/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,xinzweb/gpdb,50wu/gpdb,edespino/gpdb,adam8157/gpdb,Chibin/gpdb,lisakowen/gpdb,edespino/gpdb,yuanzhao/gpdb,edespino/gpdb,Chibin/gpdb,Chibin/gpdb,greenplum-db/gpdb,edespino/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,lisakowen/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,xinzweb/gpdb,ashwinstar/gpdb,50wu/gpdb,Chibin/gpdb,xinzweb/gpdb,greenplum-db/gpdb,ashwinstar/gpdb