build: factor out AM_LINK command (trivial)
build: factor out AM_LINK command (trivial)

Summary:
  Many link commands were identical.
  Factor that out into a variable, AM_LINK, and use
  it in place of all of those open-coded commands.

Test Plan: run "make check"

Reviewers: ljin, igor, sdong

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D33585

wat-ze-hex/rocksdb,RyanTech/rocksdb,siddhartharay007/rocksdb,Vaisman/rocksdb,Applied-Duality/rocksdb,wat-ze-hex/rocksdb,JoeWoo/rocksdb,flabby/rocksdb,sorphi/rocksdb,alihalabyah/rocksdb,tizzybec/rocksdb,Applied-Duality/rocksdb,Vaisman/rocksdb,JohnPJenkins/rocksdb,virtdb/rocksdb,tsheasha/rocksdb,sorphi/rocksdb,JackLian/rocksdb,rDSN-Projects/rocksdb.replicated,vmx/rocksdb,ylong/rocksdb,ryneli/rocksdb,tsheasha/rocksdb,geraldoandradee/rocksdb,hobinyoon/rocksdb,tsheasha/rocksdb,norton/rocksdb,ryneli/rocksdb,facebook/rocksdb,ylong/rocksdb,caijieming-baidu/rocksdb,rDSN-Projects/rocksdb.replicated,fengshao0907/rocksdb,mbarbon/rocksdb,alihalabyah/rocksdb,flabby/rocksdb,bbiao/rocksdb,rDSN-Projects/rocksdb.replicated,temicai/rocksdb,wat-ze-hex/rocksdb,geraldoandradee/rocksdb,skunkwerks/rocksdb,Vaisman/rocksdb,lgscofield/rocksdb,OverlordQ/rocksdb,amyvmiwei/rocksdb,norton/rocksdb,Applied-Duality/rocksdb,geraldoandradee/rocksdb,NickCis/rocksdb,hobinyoon/rocksdb,sorphi/rocksdb,luckywhu/rocksdb,jalexanderqed/rocksdb,IMCG/RcoksDB,fengshao0907/rocksdb,lgscofield/rocksdb,NickCis/rocksdb,vmx/rocksdb,JoeWoo/rocksdb,JoeWoo/rocksdb,IMCG/RcoksDB,facebook/rocksdb,Applied-Duality/rocksdb,bbiao/rocksdb,wat-ze-hex/rocksdb,JackLian/rocksdb,siddhartharay007/rocksdb,tizzybec/rocksdb,makelivedotnet/rocksdb,kaschaeffer/rocksdb,anagav/rocksdb,fengshao0907/rocksdb,tizzybec/rocksdb,rDSN-Projects/rocksdb.replicated,SunguckLee/RocksDB,SunguckLee/RocksDB,tizzybec/rocksdb,norton/rocksdb,zhangpng/rocksdb,biddyweb/rocksdb,fengshao0907/rocksdb,caijieming-baidu/rocksdb,biddyweb/rocksdb,luckywhu/rocksdb,JackLian/rocksdb,wlqGit/rocksdb,wskplho/rocksdb,caijieming-baidu/rocksdb,fengshao0907/rocksdb,makelivedotnet/rocksdb,NickCis/rocksdb,vmx/rocksdb,Andymic/rocksdb,wenduo/rocksdb,jalexanderqed/rocksdb,dkorolev/rocksdb,wlqGit/rocksdb,RyanTech/rocksdb,temicai/rocksdb,facebook/rocksdb,makelivedotnet/rocksdb,wlqGit/rocksdb,vashstorm/rocksdb,anagav/rocksdb,amyvmiwei/rocksdb,OverlordQ/rocksdb,zhangpng/rocksdb,Applied-Duality/rocksdb,zhangpng/rocksdb,ylong/rocksdb,IMCG/RcoksDB,virtdb/rocksdb,biddyweb/rocksdb,OverlordQ/rocksdb,tsheasha/rocksdb,ryneli/rocksdb,ryneli/rocksdb,SunguckLee/RocksDB,biddyweb/rocksdb,wlqGit/rocksdb,kaschaeffer/rocksdb,siddhartharay007/rocksdb,amyvmiwei/rocksdb,IMCG/RcoksDB,siddhartharay007/rocksdb,JoeWoo/rocksdb,jalexanderqed/rocksdb,flabby/rocksdb,temicai/rocksdb,virtdb/rocksdb,vashstorm/rocksdb,temicai/rocksdb,RyanTech/rocksdb,RyanTech/rocksdb,wlqGit/rocksdb,ryneli/rocksdb,geraldoandradee/rocksdb,luckywhu/rocksdb,alihalabyah/rocksdb,NickCis/rocksdb,flabby/rocksdb,kaschaeffer/rocksdb,RyanTech/rocksdb,wskplho/rocksdb,luckywhu/rocksdb,JohnPJenkins/rocksdb,kaschaeffer/rocksdb,virtdb/rocksdb,vmx/rocksdb,wskplho/rocksdb,hobinyoon/rocksdb,vmx/rocksdb,lgscofield/rocksdb,skunkwerks/rocksdb,temicai/rocksdb,makelivedotnet/rocksdb,skunkwerks/rocksdb,temicai/rocksdb,mbarbon/rocksdb,Vaisman/rocksdb,siddhartharay007/rocksdb,Andymic/rocksdb,vashstorm/rocksdb,lgscofield/rocksdb,tsheasha/rocksdb,amyvmiwei/rocksdb,skunkwerks/rocksdb,OverlordQ/rocksdb,Andymic/rocksdb,mbarbon/rocksdb,rDSN-Projects/rocksdb.replicated,bbiao/rocksdb,anagav/rocksdb,amyvmiwei/rocksdb,dkorolev/rocksdb,skunkwerks/rocksdb,SunguckLee/RocksDB,ylong/rocksdb,wenduo/rocksdb,JackLian/rocksdb,tizzybec/rocksdb,SunguckLee/RocksDB,IMCG/RcoksDB,dkorolev/rocksdb,wlqGit/rocksdb,luckywhu/rocksdb,zhangpng/rocksdb,jalexanderqed/rocksdb,ylong/rocksdb,anagav/rocksdb,sorphi/rocksdb,alihalabyah/rocksdb,caijieming-baidu/rocksdb,virtdb/rocksdb,lgscofield/rocksdb,dkorolev/rocksdb,dkorolev/rocksdb,facebook/rocksdb,JohnPJenkins/rocksdb,makelivedotnet/rocksdb,norton/rocksdb,IMCG/RcoksDB,Vaisman/rocksdb,Applied-Duality/rocksdb,Applied-Duality/rocksdb,kaschaeffer/rocksdb,JoeWoo/rocksdb,virtdb/rocksdb,biddyweb/rocksdb,zhangpng/rocksdb,amyvmiwei/rocksdb,sorphi/rocksdb,vashstorm/rocksdb,IMCG/RcoksDB,JohnPJenkins/rocksdb,tsheasha/rocksdb,RyanTech/rocksdb,hobinyoon/rocksdb,zhangpng/rocksdb,wenduo/rocksdb,sorphi/rocksdb,Andymic/rocksdb,wlqGit/rocksdb,wskplho/rocksdb,luckywhu/rocksdb,Vaisman/rocksdb,tizzybec/rocksdb,zhangpng/rocksdb,OverlordQ/rocksdb,wenduo/rocksdb,vashstorm/rocksdb,wenduo/rocksdb,norton/rocksdb,NickCis/rocksdb,alihalabyah/rocksdb,bbiao/rocksdb,NickCis/rocksdb,geraldoandradee/rocksdb,tizzybec/rocksdb,SunguckLee/RocksDB,hobinyoon/rocksdb,vmx/rocksdb,wskplho/rocksdb,ryneli/rocksdb,norton/rocksdb,OverlordQ/rocksdb,rDSN-Projects/rocksdb.replicated,wenduo/rocksdb,vashstorm/rocksdb,facebook/rocksdb,siddhartharay007/rocksdb,NickCis/rocksdb,alihalabyah/rocksdb,mbarbon/rocksdb,flabby/rocksdb,OverlordQ/rocksdb,luckywhu/rocksdb,tsheasha/rocksdb,mbarbon/rocksdb,skunkwerks/rocksdb,biddyweb/rocksdb,wat-ze-hex/rocksdb,flabby/rocksdb,ylong/rocksdb,lgscofield/rocksdb,JohnPJenkins/rocksdb,wskplho/rocksdb,wat-ze-hex/rocksdb,wenduo/rocksdb,makelivedotnet/rocksdb,Andymic/rocksdb,JohnPJenkins/rocksdb,JackLian/rocksdb,norton/rocksdb,vmx/rocksdb,facebook/rocksdb,vmx/rocksdb,JoeWoo/rocksdb,wskplho/rocksdb,Andymic/rocksdb,kaschaeffer/rocksdb,anagav/rocksdb,facebook/rocksdb,caijieming-baidu/rocksdb,Andymic/rocksdb,bbiao/rocksdb,Vaisman/rocksdb,kaschaeffer/rocksdb,tsheasha/rocksdb,anagav/rocksdb,norton/rocksdb,temicai/rocksdb,hobinyoon/rocksdb,ryneli/rocksdb,facebook/rocksdb,bbiao/rocksdb,virtdb/rocksdb,skunkwerks/rocksdb,fengshao0907/rocksdb,wat-ze-hex/rocksdb,anagav/rocksdb,mbarbon/rocksdb,vashstorm/rocksdb,sorphi/rocksdb,wenduo/rocksdb,siddhartharay007/rocksdb,JackLian/rocksdb,makelivedotnet/rocksdb,geraldoandradee/rocksdb,SunguckLee/RocksDB,mbarbon/rocksdb,dkorolev/rocksdb,dkorolev/rocksdb,geraldoandradee/rocksdb,JohnPJenkins/rocksdb,bbiao/rocksdb,hobinyoon/rocksdb,alihalabyah/rocksdb,JackLian/rocksdb,ylong/rocksdb,amyvmiwei/rocksdb,hobinyoon/rocksdb,bbiao/rocksdb,jalexanderqed/rocksdb,biddyweb/rocksdb,wat-ze-hex/rocksdb,RyanTech/rocksdb,rDSN-Projects/rocksdb.replicated,lgscofield/rocksdb,jalexanderqed/rocksdb,Andymic/rocksdb,JoeWoo/rocksdb,fengshao0907/rocksdb,jalexanderqed/rocksdb,caijieming-baidu/rocksdb,caijieming-baidu/rocksdb,SunguckLee/RocksDB,flabby/rocksdb