Add missing extern.h file
Add missing extern.h file

techdragon/Postgres-XL,xuegang/gpdb,kmjungersen/PostgresXL,adam8157/gpdb,greenplum-db/gpdb,kmjungersen/PostgresXL,Quikling/gpdb,50wu/gpdb,lisakowen/gpdb,lpetrov-pivotal/gpdb,rvs/gpdb,kaknikhil/gpdb,janebeckman/gpdb,lpetrov-pivotal/gpdb,edespino/gpdb,50wu/gpdb,0x0FFF/gpdb,ovr/postgres-xl,pavanvd/postgres-xl,lpetrov-pivotal/gpdb,Quikling/gpdb,royc1/gpdb,0x0FFF/gpdb,janebeckman/gpdb,postmind-net/postgres-xl,lpetrov-pivotal/gpdb,tangp3/gpdb,Chibin/gpdb,lintzc/gpdb,rubikloud/gpdb,Quikling/gpdb,zeroae/postgres-xl,zeroae/postgres-xl,postmind-net/postgres-xl,snaga/postgres-xl,zeroae/postgres-xl,chrishajas/gpdb,rvs/gpdb,adam8157/gpdb,tangp3/gpdb,janebeckman/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,xuegang/gpdb,jmcatamney/gpdb,xinzweb/gpdb,CraigHarris/gpdb,lpetrov-pivotal/gpdb,chrishajas/gpdb,yuanzhao/gpdb,kaknikhil/gpdb,Postgres-XL/Postgres-XL,kmjungersen/PostgresXL,chrishajas/gpdb,rubikloud/gpdb,rubikloud/gpdb,lisakowen/gpdb,arcivanov/postgres-xl,royc1/gpdb,atris/gpdb,yuanzhao/gpdb,atris/gpdb,adam8157/gpdb,tpostgres-projects/tPostgres,cjcjameson/gpdb,atris/gpdb,Quikling/gpdb,zaksoup/gpdb,edespino/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,snaga/postgres-xl,Chibin/gpdb,rvs/gpdb,lisakowen/gpdb,lintzc/gpdb,randomtask1155/gpdb,lintzc/gpdb,rubikloud/gpdb,tpostgres-projects/tPostgres,royc1/gpdb,xinzweb/gpdb,greenplum-db/gpdb,postmind-net/postgres-xl,tangp3/gpdb,kaknikhil/gpdb,xinzweb/gpdb,50wu/gpdb,xinzweb/gpdb,randomtask1155/gpdb,Quikling/gpdb,Postgres-XL/Postgres-XL,edespino/gpdb,tangp3/gpdb,randomtask1155/gpdb,yazun/postgres-xl,rvs/gpdb,edespino/gpdb,atris/gpdb,greenplum-db/gpdb,CraigHarris/gpdb,yuanzhao/gpdb,zaksoup/gpdb,rvs/gpdb,ovr/postgres-xl,cjcjameson/gpdb,ashwinstar/gpdb,zaksoup/gpdb,greenplum-db/gpdb,adam8157/gpdb,randomtask1155/gpdb,rubikloud/gpdb,postmind-net/postgres-xl,rubikloud/gpdb,ahachete/gpdb,chrishajas/gpdb,foyzur/gpdb,oberstet/postgres-xl,adam8157/gpdb,janebeckman/gpdb,kaknikhil/gpdb,xinzweb/gpdb,foyzur/gpdb,rubikloud/gpdb,yuanzhao/gpdb,xuegang/gpdb,yuanzhao/gpdb,Postgres-XL/Postgres-XL,Quikling/gpdb,rvs/gpdb,Quikling/gpdb,zaksoup/gpdb,lintzc/gpdb,tangp3/gpdb,xuegang/gpdb,cjcjameson/gpdb,kaknikhil/gpdb,edespino/gpdb,lintzc/gpdb,lpetrov-pivotal/gpdb,janebeckman/gpdb,rvs/gpdb,tangp3/gpdb,edespino/gpdb,randomtask1155/gpdb,kmjungersen/PostgresXL,edespino/gpdb,lisakowen/gpdb,arcivanov/postgres-xl,zaksoup/gpdb,pavanvd/postgres-xl,CraigHarris/gpdb,snaga/postgres-xl,atris/gpdb,oberstet/postgres-xl,adam8157/gpdb,techdragon/Postgres-XL,CraigHarris/gpdb,ashwinstar/gpdb,xuegang/gpdb,kaknikhil/gpdb,zaksoup/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,chrishajas/gpdb,arcivanov/postgres-xl,cjcjameson/gpdb,postmind-net/postgres-xl,Postgres-XL/Postgres-XL,randomtask1155/gpdb,adam8157/gpdb,lintzc/gpdb,zeroae/postgres-xl,Chibin/gpdb,atris/gpdb,rvs/gpdb,rvs/gpdb,yuanzhao/gpdb,cjcjameson/gpdb,edespino/gpdb,Chibin/gpdb,kaknikhil/gpdb,50wu/gpdb,lisakowen/gpdb,jmcatamney/gpdb,arcivanov/postgres-xl,greenplum-db/gpdb,Quikling/gpdb,ahachete/gpdb,ahachete/gpdb,randomtask1155/gpdb,chrishajas/gpdb,zaksoup/gpdb,Quikling/gpdb,0x0FFF/gpdb,foyzur/gpdb,xinzweb/gpdb,royc1/gpdb,janebeckman/gpdb,lintzc/gpdb,techdragon/Postgres-XL,ahachete/gpdb,Quikling/gpdb,pavanvd/postgres-xl,xinzweb/gpdb,CraigHarris/gpdb,ashwinstar/gpdb,xuegang/gpdb,atris/gpdb,kaknikhil/gpdb,ovr/postgres-xl,yazun/postgres-xl,Chibin/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,0x0FFF/gpdb,50wu/gpdb,foyzur/gpdb,yazun/postgres-xl,atris/gpdb,ahachete/gpdb,Chibin/gpdb,janebeckman/gpdb,50wu/gpdb,zaksoup/gpdb,0x0FFF/gpdb,xuegang/gpdb,cjcjameson/gpdb,kaknikhil/gpdb,royc1/gpdb,yazun/postgres-xl,tangp3/gpdb,tangp3/gpdb,CraigHarris/gpdb,snaga/postgres-xl,kmjungersen/PostgresXL,ovr/postgres-xl,tpostgres-projects/tPostgres,ashwinstar/gpdb,Chibin/gpdb,arcivanov/postgres-xl,lpetrov-pivotal/gpdb,Chibin/gpdb,snaga/postgres-xl,CraigHarris/gpdb,foyzur/gpdb,lpetrov-pivotal/gpdb,tpostgres-projects/tPostgres,randomtask1155/gpdb,ovr/postgres-xl,lisakowen/gpdb,techdragon/Postgres-XL,ahachete/gpdb,0x0FFF/gpdb,Chibin/gpdb,yazun/postgres-xl,adam8157/gpdb,janebeckman/gpdb,cjcjameson/gpdb,edespino/gpdb,ahachete/gpdb,kaknikhil/gpdb,royc1/gpdb,foyzur/gpdb,rubikloud/gpdb,techdragon/Postgres-XL,oberstet/postgres-xl,ashwinstar/gpdb,janebeckman/gpdb,yuanzhao/gpdb,50wu/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,CraigHarris/gpdb,chrishajas/gpdb,lintzc/gpdb,royc1/gpdb,arcivanov/postgres-xl,Chibin/gpdb,xinzweb/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,foyzur/gpdb,yuanzhao/gpdb,cjcjameson/gpdb,tpostgres-projects/tPostgres,jmcatamney/gpdb,foyzur/gpdb,oberstet/postgres-xl,lisakowen/gpdb,pavanvd/postgres-xl,pavanvd/postgres-xl,edespino/gpdb,0x0FFF/gpdb,rvs/gpdb,50wu/gpdb,cjcjameson/gpdb,0x0FFF/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,chrishajas/gpdb,zeroae/postgres-xl,janebeckman/gpdb,royc1/gpdb,lintzc/gpdb,xuegang/gpdb,xuegang/gpdb,CraigHarris/gpdb,ahachete/gpdb,lisakowen/gpdb