util/xfunc.h: fix #elif check for NDEBUG
util/xfunc.h: fix #elif check for NDEBUG

Fix '#elif with no expression', add defined() to check.

Signed-off-by: Danny Al-Gaaf <473e39ac77cf392f0dd9bacde8409de76c14d006@bisect.de>

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