Update Build CoreCLR Instructions on Mac OS X.
Update Build CoreCLR Instructions on Mac OS X.

Rebuild option is not handled in build.sh.  Hence removing the sentence
that suggests using a rebuild option that will delete previously built
assemblies.

bartonjs/coreclr,Godin/coreclr,martinwoodward/coreclr,schellap/coreclr,sperling/coreclr,serenabenny/coreclr,DasAllFolks/coreclr,cydhaselton/coreclr,iamjasonp/coreclr,krytarowski/coreclr,bartonjs/coreclr,LLITCHEV/coreclr,mocsy/coreclr,DasAllFolks/coreclr,DasAllFolks/coreclr,ktos/coreclr,xoofx/coreclr,mskvortsov/coreclr,mocsy/coreclr,JonHanna/coreclr,ZhichengZhu/coreclr,benpye/coreclr,gkhanna79/coreclr,ericeil/coreclr,James-Ko/coreclr,yizhang82/coreclr,parjong/coreclr,JosephTremoulet/coreclr,benpye/coreclr,taylorjonl/coreclr,DasAllFolks/coreclr,neurospeech/coreclr,KrzysztofCwalina/coreclr,poizan42/coreclr,sejongoh/coreclr,Dmitry-Me/coreclr,chaos7theory/coreclr,iamjasonp/coreclr,hseok-oh/coreclr,cydhaselton/coreclr,tijoytom/coreclr,SlavaRa/coreclr,SlavaRa/coreclr,LLITCHEV/coreclr,geertdoornbos/coreclr,schellap/coreclr,mocsy/coreclr,serenabenny/coreclr,tijoytom/coreclr,manu-silicon/coreclr,mocsy/coreclr,swgillespie/coreclr,sjsinju/coreclr,jhendrixMSFT/coreclr,cydhaselton/coreclr,parjong/coreclr,zmaruo/coreclr,parjong/coreclr,chuck-mitchell/coreclr,Samana/coreclr,AlfredoMS/coreclr,wkchoy74/coreclr,mmitche/coreclr,stormleoxia/coreclr,AlfredoMS/coreclr,mskvortsov/coreclr,bitcrazed/coreclr,KrzysztofCwalina/coreclr,Godin/coreclr,kyulee1/coreclr,mokchhya/coreclr,yeaicc/coreclr,martinwoodward/coreclr,Sridhar-MS/coreclr,manu-silicon/coreclr,dasMulli/coreclr,jamesqo/coreclr,roncain/coreclr,krk/coreclr,tijoytom/coreclr,roncain/coreclr,kyulee1/coreclr,cmckinsey/coreclr,ramarag/coreclr,alexperovich/coreclr,poizan42/coreclr,AlfredoMS/coreclr,vinnyrom/coreclr,jamesqo/coreclr,dasMulli/coreclr,YongseopKim/coreclr,ZhichengZhu/coreclr,sagood/coreclr,bartdesmet/coreclr,Sridhar-MS/coreclr,chaos7theory/coreclr,MCGPPeters/coreclr,Dmitry-Me/coreclr,MCGPPeters/coreclr,chrishaly/coreclr,cshung/coreclr,bitcrazed/coreclr,perfectphase/coreclr,Alcaro/coreclr,zmaruo/coreclr,taylorjonl/coreclr,bartonjs/coreclr,sejongoh/coreclr,Djuffin/coreclr,geertdoornbos/coreclr,sperling/coreclr,vinnyrom/coreclr,wtgodbe/coreclr,dasMulli/coreclr,sperling/coreclr,MCGPPeters/coreclr,JosephTremoulet/coreclr,serenabenny/coreclr,stormleoxia/coreclr,ericeil/coreclr,manu-silicon/coreclr,ramarag/coreclr,wtgodbe/coreclr,chuck-mitchell/coreclr,stormleoxia/coreclr,orthoxerox/coreclr,mskvortsov/coreclr,LLITCHEV/coreclr,dpodder/coreclr,sperling/coreclr,russellhadley/coreclr,James-Ko/coreclr,blackdwarf/coreclr,Alcaro/coreclr,andschwa/coreclr,Alcaro/coreclr,sperling/coreclr,swgillespie/coreclr,neurospeech/coreclr,dpodder/coreclr,russellhadley/coreclr,OryJuVog/coreclr,ericeil/coreclr,cshung/coreclr,swgillespie/coreclr,OryJuVog/coreclr,gkhanna79/coreclr,JonHanna/coreclr,benpye/coreclr,Alcaro/coreclr,zmaruo/coreclr,mokchhya/coreclr,ktos/coreclr,pgavlin/coreclr,iamjasonp/coreclr,ktos/coreclr,blackdwarf/coreclr,perfectphase/coreclr,yeaicc/coreclr,cshung/coreclr,Samana/coreclr,pgavlin/coreclr,parjong/coreclr,AlexGhiondea/coreclr,rartemev/coreclr,Alcaro/coreclr,qiudesong/coreclr,cmckinsey/coreclr,alexperovich/coreclr,tijoytom/coreclr,swgillespie/coreclr,botaberg/coreclr,Lucrecious/coreclr,naamunds/coreclr,wtgodbe/coreclr,sjsinju/coreclr,neurospeech/coreclr,bartdesmet/coreclr,martinwoodward/coreclr,AlfredoMS/coreclr,James-Ko/coreclr,AlfredoMS/coreclr,schellap/coreclr,sagood/coreclr,jamesqo/coreclr,jhendrixMSFT/coreclr,Lucrecious/coreclr,stormleoxia/coreclr,botaberg/coreclr,zmaruo/coreclr,dpodder/coreclr,KrzysztofCwalina/coreclr,ramarag/coreclr,russellhadley/coreclr,cmckinsey/coreclr,mmitche/coreclr,hseok-oh/coreclr,jhendrixMSFT/coreclr,schellap/coreclr,Dmitry-Me/coreclr,gkhanna79/coreclr,chrishaly/coreclr,wateret/coreclr,stormleoxia/coreclr,yeaicc/coreclr,krk/coreclr,mmitche/coreclr,ruben-ayrapetyan/coreclr,chrishaly/coreclr,krytarowski/coreclr,chrishaly/coreclr,iamjasonp/coreclr,AlexGhiondea/coreclr,SlavaRa/coreclr,sperling/coreclr,benpye/coreclr,poizan42/coreclr,MCGPPeters/coreclr,Godin/coreclr,sjsinju/coreclr,alexperovich/coreclr,ragmani/coreclr,Djuffin/coreclr,roncain/coreclr,ruben-ayrapetyan/coreclr,yeaicc/coreclr,andschwa/coreclr,roncain/coreclr,Lucrecious/coreclr,jhendrixMSFT/coreclr,blackdwarf/coreclr,roncain/coreclr,taylorjonl/coreclr,taylorjonl/coreclr,ramarag/coreclr,josteink/coreclr,ericeil/coreclr,ruben-ayrapetyan/coreclr,KrzysztofCwalina/coreclr,poizan42/coreclr,xoofx/coreclr,manu-silicon/coreclr,Godin/coreclr,jamesqo/coreclr,wtgodbe/coreclr,jhendrixMSFT/coreclr,josteink/coreclr,sjsinju/coreclr,martinwoodward/coreclr,wkchoy74/coreclr,shahid-pk/coreclr,LLITCHEV/coreclr,geertdoornbos/coreclr,Samana/coreclr,alexperovich/coreclr,neurospeech/coreclr,hseok-oh/coreclr,mmitche/coreclr,qiudesong/coreclr,andschwa/coreclr,kyulee1/coreclr,krixalis/coreclr,Godin/coreclr,cmckinsey/coreclr,ZhichengZhu/coreclr,qiudesong/coreclr,krytarowski/coreclr,Dmitry-Me/coreclr,krytarowski/coreclr,ramarag/coreclr,Djuffin/coreclr,benpye/coreclr,chuck-mitchell/coreclr,krytarowski/coreclr,andschwa/coreclr,ruben-ayrapetyan/coreclr,mskvortsov/coreclr,James-Ko/coreclr,sejongoh/coreclr,Samana/coreclr,SlavaRa/coreclr,ruben-ayrapetyan/coreclr,perfectphase/coreclr,AlfredoMS/coreclr,ZhichengZhu/coreclr,mokchhya/coreclr,geertdoornbos/coreclr,ktos/coreclr,vinnyrom/coreclr,bartonjs/coreclr,bartdesmet/coreclr,Djuffin/coreclr,bartonjs/coreclr,qiudesong/coreclr,krk/coreclr,bartdesmet/coreclr,mokchhya/coreclr,manu-silicon/coreclr,jamesqo/coreclr,roncain/coreclr,rartemev/coreclr,OryJuVog/coreclr,sjsinju/coreclr,shahid-pk/coreclr,pgavlin/coreclr,poizan42/coreclr,AlexGhiondea/coreclr,josteink/coreclr,blackdwarf/coreclr,mskvortsov/coreclr,MCGPPeters/coreclr,sperling/coreclr,josteink/coreclr,ramarag/coreclr,SlavaRa/coreclr,YongseopKim/coreclr,perfectphase/coreclr,botaberg/coreclr,JonHanna/coreclr,chaos7theory/coreclr,geertdoornbos/coreclr,chaos7theory/coreclr,shahid-pk/coreclr,JosephTremoulet/coreclr,pgavlin/coreclr,ragmani/coreclr,cydhaselton/coreclr,ragmani/coreclr,jhendrixMSFT/coreclr,Samana/coreclr,serenabenny/coreclr,LLITCHEV/coreclr,Dmitry-Me/coreclr,yeaicc/coreclr,neurospeech/coreclr,rartemev/coreclr,YongseopKim/coreclr,pgavlin/coreclr,alexperovich/coreclr,cmckinsey/coreclr,qiudesong/coreclr,martinwoodward/coreclr,naamunds/coreclr,chrishaly/coreclr,Alcaro/coreclr,botaberg/coreclr,chrishaly/coreclr,ktos/coreclr,DasAllFolks/coreclr,OryJuVog/coreclr,krixalis/coreclr,tijoytom/coreclr,wtgodbe/coreclr,manu-silicon/coreclr,gkhanna79/coreclr,yeaicc/coreclr,ktos/coreclr,wateret/coreclr,bartdesmet/coreclr,wateret/coreclr,dasMulli/coreclr,benpye/coreclr,Lucrecious/coreclr,krixalis/coreclr,orthoxerox/coreclr,DasAllFolks/coreclr,James-Ko/coreclr,Sridhar-MS/coreclr,ragmani/coreclr,jhendrixMSFT/coreclr,AlexGhiondea/coreclr,josteink/coreclr,serenabenny/coreclr,bartonjs/coreclr,shahid-pk/coreclr,yizhang82/coreclr,LLITCHEV/coreclr,iamjasonp/coreclr,sagood/coreclr,cshung/coreclr,rartemev/coreclr,mmitche/coreclr,swgillespie/coreclr,KrzysztofCwalina/coreclr,mskvortsov/coreclr,dasMulli/coreclr,kyulee1/coreclr,Djuffin/coreclr,chuck-mitchell/coreclr,krytarowski/coreclr,ramarag/coreclr,orthoxerox/coreclr,xoofx/coreclr,sejongoh/coreclr,chuck-mitchell/coreclr,shahid-pk/coreclr,ragmani/coreclr,wkchoy74/coreclr,krk/coreclr,perfectphase/coreclr,naamunds/coreclr,neurospeech/coreclr,cmckinsey/coreclr,bitcrazed/coreclr,orthoxerox/coreclr,shahid-pk/coreclr,hseok-oh/coreclr,chuck-mitchell/coreclr,mocsy/coreclr,ericeil/coreclr,cmckinsey/coreclr,Sridhar-MS/coreclr,xoofx/coreclr,naamunds/coreclr,MCGPPeters/coreclr,benpye/coreclr,martinwoodward/coreclr,tijoytom/coreclr,JosephTremoulet/coreclr,bitcrazed/coreclr,cshung/coreclr,cydhaselton/coreclr,qiudesong/coreclr,vinnyrom/coreclr,naamunds/coreclr,yizhang82/coreclr,orthoxerox/coreclr,chaos7theory/coreclr,poizan42/coreclr,bartdesmet/coreclr,parjong/coreclr,Samana/coreclr,yeaicc/coreclr,krixalis/coreclr,bitcrazed/coreclr,Dmitry-Me/coreclr,krixalis/coreclr,rartemev/coreclr,schellap/coreclr,naamunds/coreclr,ZhichengZhu/coreclr,Lucrecious/coreclr,chaos7theory/coreclr,wkchoy74/coreclr,parjong/coreclr,xoofx/coreclr,manu-silicon/coreclr,bitcrazed/coreclr,JosephTremoulet/coreclr,andschwa/coreclr,stormleoxia/coreclr,OryJuVog/coreclr,geertdoornbos/coreclr,zmaruo/coreclr,YongseopKim/coreclr,serenabenny/coreclr,dpodder/coreclr,perfectphase/coreclr,botaberg/coreclr,dasMulli/coreclr,iamjasonp/coreclr,mokchhya/coreclr,wkchoy74/coreclr,kyulee1/coreclr,AlexGhiondea/coreclr,dpodder/coreclr,stormleoxia/coreclr,mocsy/coreclr,vinnyrom/coreclr,chuck-mitchell/coreclr,ericeil/coreclr,sejongoh/coreclr,orthoxerox/coreclr,xoofx/coreclr,russellhadley/coreclr,jamesqo/coreclr,blackdwarf/coreclr,rartemev/coreclr,taylorjonl/coreclr,zmaruo/coreclr,schellap/coreclr,pgavlin/coreclr,OryJuVog/coreclr,LLITCHEV/coreclr,mokchhya/coreclr,wkchoy74/coreclr,wtgodbe/coreclr,martinwoodward/coreclr,alexperovich/coreclr,Lucrecious/coreclr,JonHanna/coreclr,Godin/coreclr,bartdesmet/coreclr,russellhadley/coreclr,Dmitry-Me/coreclr,kyulee1/coreclr,ZhichengZhu/coreclr,josteink/coreclr,mokchhya/coreclr,hseok-oh/coreclr,naamunds/coreclr,blackdwarf/coreclr,vinnyrom/coreclr,KrzysztofCwalina/coreclr,JonHanna/coreclr,KrzysztofCwalina/coreclr,JonHanna/coreclr,sagood/coreclr,wateret/coreclr,wateret/coreclr,wateret/coreclr,andschwa/coreclr,mmitche/coreclr,krk/coreclr,ragmani/coreclr,taylorjonl/coreclr,dpodder/coreclr,yizhang82/coreclr,taylorjonl/coreclr,krk/coreclr,Sridhar-MS/coreclr,swgillespie/coreclr,schellap/coreclr,YongseopKim/coreclr,swgillespie/coreclr,geertdoornbos/coreclr,Lucrecious/coreclr,sejongoh/coreclr,krixalis/coreclr,sjsinju/coreclr,Sridhar-MS/coreclr,sagood/coreclr,wkchoy74/coreclr,James-Ko/coreclr,dasMulli/coreclr,vinnyrom/coreclr,josteink/coreclr,mocsy/coreclr,sejongoh/coreclr,ZhichengZhu/coreclr,YongseopKim/coreclr,gkhanna79/coreclr,SlavaRa/coreclr,hseok-oh/coreclr,russellhadley/coreclr,ruben-ayrapetyan/coreclr,Djuffin/coreclr,blackdwarf/coreclr,bitcrazed/coreclr,JosephTremoulet/coreclr,bartonjs/coreclr,Godin/coreclr,AlexGhiondea/coreclr,yizhang82/coreclr,botaberg/coreclr,andschwa/coreclr,cshung/coreclr,sagood/coreclr,ktos/coreclr,roncain/coreclr,shahid-pk/coreclr,gkhanna79/coreclr,cydhaselton/coreclr,yizhang82/coreclr