Add detection of MSVC RTTI
Add detection of MSVC RTTI

Summary: This adds MSVC support to the detection of FOLLY_HAS_RTTI.
Closes #255

Reviewed By: @yfeldblum

Differential Revision: D2283036

Pulled By: @sgolemon

yangjin-unique/folly,SeanRBurton/folly,arg0/folly,sonnyhu/folly,reddit/folly,stonegithubs/folly,facebook/folly,bowlofstew/folly,SammyK/folly,raphaelamorim/folly,wildinto/folly,constantine001/folly,leolujuyi/folly,xzmagic/folly,loversInJapan/folly,arg0/folly,PoisonBOx/folly,chjp2046/folly,SeanRBurton/folly,renyinew/folly,charsyam/folly,zhiweicai/folly,theiver9827/folly,Orvid/folly,hongliangzhao/folly,clearlylin/folly,tomhughes/folly,zhiweicai/folly,bobegir/folly,doctaweeks/folly,alexst07/folly,shaobz/folly,mqeizi/folly,leolujuyi/folly,upsoft/folly,PoisonBOx/folly,tempbottle/folly,bowlofstew/folly,chjp2046/folly,sonnyhu/folly,brunomorishita/folly,gavioto/folly,clearlylin/folly,mqeizi/folly,loversInJapan/folly,gaoyingie/folly,loversInJapan/folly,wildinto/folly,reddit/folly,lifei/folly,sakishum/folly,chjp2046/folly,zhiweicai/folly,juniway/folly,bobegir/folly,SeanRBurton/folly,yangjin-unique/folly,leolujuyi/folly,loversInJapan/folly,tempbottle/folly,zhiweicai/folly,juniway/folly,sakishum/folly,PPC64/folly,rklabs/folly,leolujuyi/folly,Eagle-X/folly,renyinew/folly,bikong2/folly,gaoyingie/folly,bikong2/folly,Orvid/folly,leolujuyi/folly,theiver9827/folly,charsyam/folly,KSreeHarsha/folly,fw1121/folly,Eagle-X/folly,tomhughes/folly,bowlofstew/folly,PPC64/folly,doctaweeks/folly,tomhughes/folly,Hincoin/folly,arg0/folly,xzmagic/folly,gavioto/folly,shaobz/folly,theiver9827/folly,clearlylin/folly,doctaweeks/folly,SammyK/folly,bobegir/folly,KSreeHarsha/folly,fw1121/folly,bobegir/folly,shaobz/folly,KSreeHarsha/folly,wildinto/folly,guker/folly,rklabs/folly,lifei/folly,SeanRBurton/folly,stonegithubs/folly,floxard/folly,guker/folly,upsoft/folly,Hincoin/folly,hongliangzhao/folly,brunomorishita/folly,Orvid/folly,loversInJapan/folly,tempbottle/folly,brunomorishita/folly,raphaelamorim/folly,sakishum/folly,constantine001/folly,reddit/folly,xzmagic/folly,tomhughes/folly,bikong2/folly,charsyam/folly,CJstar/folly,shaobz/folly,hongliangzhao/folly,brunomorishita/folly,constantine001/folly,sakishum/folly,brunomorishita/folly,guker/folly,facebook/folly,CJstar/folly,bowlofstew/folly,lifei/folly,raphaelamorim/folly,chjp2046/folly,PPC64/folly,alexst07/folly,fw1121/folly,Hincoin/folly,alexst07/folly,gaoyingie/folly,constantine001/folly,Orvid/folly,Hincoin/folly,Orvid/folly,facebook/folly,SammyK/folly,Eagle-X/folly,KSreeHarsha/folly,PoisonBOx/folly,PPC64/folly,reddit/folly,gavioto/folly,renyinew/folly,tempbottle/folly,SeanRBurton/folly,fw1121/folly,rklabs/folly,facebook/folly,mqeizi/folly,gaoyingie/folly,bowlofstew/folly,KSreeHarsha/folly,mqeizi/folly,juniway/folly,sakishum/folly,floxard/folly,bikong2/folly,bobegir/folly,CJstar/folly,SammyK/folly,PoisonBOx/folly,charsyam/folly,lifei/folly,reddit/folly,rklabs/folly,clearlylin/folly,zhiweicai/folly,CJstar/folly,gavioto/folly,stonegithubs/folly,stonegithubs/folly,arg0/folly,Eagle-X/folly,doctaweeks/folly,raphaelamorim/folly,constantine001/folly,hongliangzhao/folly,tempbottle/folly,alexst07/folly,juniway/folly,renyinew/folly,PPC64/folly,shaobz/folly,SammyK/folly,chjp2046/folly,Hincoin/folly,sonnyhu/folly,xzmagic/folly,alexst07/folly,xzmagic/folly,Eagle-X/folly,sonnyhu/folly,lifei/folly,guker/folly,gaoyingie/folly,floxard/folly,CJstar/folly,theiver9827/folly,theiver9827/folly,tomhughes/folly,renyinew/folly,yangjin-unique/folly,upsoft/folly,wildinto/folly,mqeizi/folly,raphaelamorim/folly,arg0/folly,upsoft/folly,PoisonBOx/folly,juniway/folly,gavioto/folly,doctaweeks/folly,fw1121/folly,rklabs/folly,sonnyhu/folly,guker/folly,bikong2/folly,yangjin-unique/folly,clearlylin/folly,facebook/folly,floxard/folly,upsoft/folly,hongliangzhao/folly,stonegithubs/folly,yangjin-unique/folly,floxard/folly,wildinto/folly