use CONST macro for OSX. BUG=254 TEST=none R=johannkoenig@google.com
use CONST macro for OSX.
BUG=254
TEST=none
R=johannkoenig@google.com

Review URL: https://webrtc-codereview.appspot.com/1942004
changchang/libyuv,gengchenglin/libyuv,ddpatel2606/libyuv,alfatraining/libyuv,nanguantong/libyuv,patrickcusack/libyuv,sigysmund/libyuv,BigMing001/libyuv,lemoon/libyuv,Shamim1977/libyuv,lyx2014/libyuv,sepcity/libyuv,FAHADSUST/libyuv,liuzhe02/libyuv,Shamim1977/libyuv,dong83615/libyuv,envyen/libyuv,zpc930/libyuv,Shamim1977/libyuv,alfatraining/libyuv,muslim1977/libyuv,JuannyWang/libyuv,Locnath/libyuv,dreamcoder/libyuv,wow2006/libyuv,sepcity/libyuv,wow2006/libyuv,gengchenglin/libyuv,Evgeniy-Odesskiy/libyuv,cjr1983/libyuv,xcl010/libyuv,weifud/libyuv,ddpatel2606/libyuv,skyofdwarf/libyuv,swak/libyuv,JuannyWang/libyuv,EdgarMora/libyuv,theunreplicated/libyuv,sigysmund/libyuv,foolab/libyuv,oiramario/libyuv,codyc/libyuv,skyofdwarf/libyuv,tectronics/libyuv,hongqingquan/libyuv,happy-star/libyuv,pecoco/libyuv,pecoco/libyuv,fjyihan/libyuv,stephenyin/libyuv,koxiong/libyuv,andriy-yermakov/libyuv,binsys/libyuv,gavinljj/libyuv,lemoon/libyuv,tony2012/libyuv,patrickcusack/libyuv,wmiller848/libyuv,leetaizhu/libyuv,fjyihan/libyuv,JuannyWang/libyuv,virneo/libyuv,zj2089/libyuv,theunreplicated/libyuv,EdgarMora/libyuv,binsys/libyuv,jhanay/libyuv,andriy-yermakov/libyuv,FAHADSUST/libyuv,kiwifig/libyuv,Locnath/libyuv,oiramario/libyuv,Malek44/libyuv,ddpatel2606/libyuv,gavinljj/libyuv,sateeshyegireddi/libyuv,polyzz/libyuv,polyzz/libyuv,kpgalligan/libyuv,Malek44/libyuv,hushuitian/libyuv,foolab/libyuv,heyfluke/libyuv,torodavit/libyuv,sateeshyegireddi/libyuv,platoon-code/libyuv,danilogr/libyuv,hongqingquan/libyuv,sitoumbaz/libyuv,bluceldg/libyuv,wanggenggz/libyuv,xiongdaofu/libyuv,zephyroal/libyuv,happy-star/libyuv,KIHOSONG/libyuv,hushuitian/libyuv,ericma2014/libyuv,Eikan/libyuv,todostreaming/libyuv,yosoymin/libyuv,Padmassri/libyuv,EdgarMora/libyuv,eterrao/libyuv,buliaoyin/libyuv,jhanay/libyuv,envyen/libyuv,kiwifig/libyuv,weifud/libyuv,todostreaming/libyuv,dreamcoder/libyuv,zhuolinho/libyuv,zpc930/libyuv,drybeans/libyuv,Ariesnix/libyuv,xiongdaofu/libyuv,koxiong/libyuv,dong83615/libyuv,gavinljj/libyuv,jrdeng/libyuv,zephyroal/libyuv,Evgeniy-Odesskiy/libyuv,mayurAzoi/libyuv,changchang/libyuv,zothen/libyuv,Ariesnix/libyuv,wow2006/libyuv,heyfluke/libyuv,Miliox/libyuv,bluceldg/libyuv,heyfluke/libyuv,kiwifig/libyuv,happy-star/libyuv,AshwanthSelvam/libyuv,lcwyylcwyy/libyuv,elkpi/libyuv,virneo/libyuv,polyzz/libyuv,yosoymin/libyuv,walletiger/libyuv,AshwanthSelvam/libyuv,lcwyylcwyy/libyuv,AshwanthSelvam/libyuv,xuruhao/libyuv,xiongdaofu/libyuv,torodavit/libyuv,sateeshyegireddi/libyuv,se7en3rd/libyuv,leetaizhu/libyuv,xuruhao/libyuv,zijay0822/libyuv,ksophocleous/libyuv,Evgeniy-Odesskiy/libyuv,ericma2014/libyuv,huangxueqin/libyuv,biotrump/libyuv,jeyluta/libyuv,mayurAzoi/libyuv,weifud/libyuv,swak/libyuv,zj2089/libyuv,eterrao/libyuv,pecoco/libyuv,eterrao/libyuv,zhuolinho/libyuv,leetaizhu/libyuv,liuzhe02/libyuv,drybeans/libyuv,danilogr/libyuv,katepanping/libyuv,walletiger/libyuv,oiramario/libyuv,cjr1983/libyuv,sepcity/libyuv,xuruhao/libyuv,tectronics/libyuv,katepanping/libyuv,jeyluta/libyuv,liuzhe02/libyuv,stephenyin/libyuv,gengchenglin/libyuv,kpgalligan/libyuv,hongqingquan/libyuv,wmiller848/libyuv,nanguantong/libyuv,mannuray/libyuv,patrickcusack/libyuv,mannuray/libyuv,jrdeng/libyuv,Miliox/libyuv,Ariesnix/libyuv,danilogr/libyuv,zj2089/libyuv,FAHADSUST/libyuv,lcwyylcwyy/libyuv,Miliox/libyuv,foolab/libyuv,lemoon/libyuv,elkpi/libyuv,tony2012/libyuv,fjyihan/libyuv,stephenyin/libyuv,theunreplicated/libyuv,codyc/libyuv,dreamcoder/libyuv,yosoymin/libyuv,KIHOSONG/libyuv,buliaoyin/libyuv,cjr1983/libyuv,KIHOSONG/libyuv,ksophocleous/libyuv,drybeans/libyuv,sitoumbaz/libyuv,xcl010/libyuv,biotrump/libyuv,muslim1977/libyuv,xcl010/libyuv,bluceldg/libyuv,Locnath/libyuv,zpc930/libyuv,dong83615/libyuv,binsys/libyuv,tony2012/libyuv,buliaoyin/libyuv,alfatraining/libyuv,mayurAzoi/libyuv,muslim1977/libyuv,jeyluta/libyuv,leeslove/libyuv,Padmassri/libyuv,zijay0822/libyuv,se7en3rd/libyuv,sitoumbaz/libyuv,tectronics/libyuv,changchang/libyuv,todostreaming/libyuv,zephyroal/libyuv,andriy-yermakov/libyuv,ksophocleous/libyuv,huangxueqin/libyuv,jrdeng/libyuv,virneo/libyuv,platoon-code/libyuv,wmiller848/libyuv,nanguantong/libyuv,codyc/libyuv,Padmassri/libyuv,zothen/libyuv,skyofdwarf/libyuv,BigMing001/libyuv,leeslove/libyuv,se7en3rd/libyuv,koxiong/libyuv,envyen/libyuv,lyx2014/libyuv,ericma2014/libyuv,Eikan/libyuv,biotrump/libyuv,Eikan/libyuv,torodavit/libyuv,huangxueqin/libyuv,katepanping/libyuv,BigMing001/libyuv,hushuitian/libyuv,alfatraining/libyuv,mannuray/libyuv,zothen/libyuv,elkpi/libyuv,zhuolinho/libyuv,Malek44/libyuv,swak/libyuv,kpgalligan/libyuv,lyx2014/libyuv,platoon-code/libyuv,wanggenggz/libyuv,zijay0822/libyuv,jhanay/libyuv,leeslove/libyuv,sigysmund/libyuv,wanggenggz/libyuv,walletiger/libyuv