Fix declarations of pthread functions, missed in recent commit.
Fix declarations of pthread functions, missed in recent commit.

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