Test for existence of inet_aton on the system, and only include inet_aton.c if required
Test for existence of inet_aton on the system, and only include inet_aton.c if
required

Pointed out by Brian E. Gallew

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