doc: document ios build tag for crypto/x509
doc: document ios build tag for crypto/x509

Change-Id: I6e6d38ae347b4f5a33dff609b89785a038bc384c
Reviewed-on: https://go-review.googlesource.com/12304
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

shishkander/go,cyberroadie/go,WIZARD-CXY/go,cloudrain21/go,nakedgc/go,mdp/go,ObjectiveJoe/go,goodlang/good,jameskumar/go,qskycolor/go,rentongzhang/go,ErikDubbelboer/go,shishkander/go,xujianhai/go,jameskumar/go,theif519/go,mgyenik/go,suncycheng/go,ObjectiveJoe/go,joshsammut/go,zhangg/go,miolini/go,odeke-em/go,gdey/go,cloudflare/go,xinhuang327/go,NunoEdgarGub1/go,CarterTsai/go,vishsingh/go,constantine001/go,ericsnowcurrently/go,malvira/go,dgnorton/go,vishsingh/go,danielsoro/go,theass/go,linux-on-ibm-z/go,kakuhiroshi/go,rentongzhang/go,danycoro/go,zhangg/go,leeric92/go,dpatel06/go,myPublicGit/go,jefby/go,CarterTsai/go,4ad/go,theif519/go,vsdutka/go,vanloswang/go,golang/go,mdp/go,NunoEdgarGub1/go,joshsammut/go,kim-racktop/go,WIZARD-CXY/go,jameskumar/go,yasarkunduz/go,uileyar/go,beealone/go,ifagnosticism/go,Pulgafree/go,albertjin/golang-go,xujianhai/go,cookerzhu/go,leeric92/go,stormltf/go,linux-on-ibm-z/go,likesea/go,youprofit/go,NichoZhang/go,shishkander/go,jefby/go,skatsuta/go,jonahglover/go,NichoZhang/go,CiscoCloud/go,wangfakang/go-1,g522342435/go,ichu501/go,joshsammut/go,cnbin/go,golang/go,mdp/go,dafyddcrosby/go,yuhengye/go,CarterTsai/go,danielsoro/go,springning/go,goodlang/good,qskycolor/go,jdhenke/go,Jordanzuo/go,theif519/go,yangzhongj/go,shazow/go,monetate/go,4ad/go,danielsoro/go,chinanjjohn2012/go,vsdutka/go,suncycheng/go,chinanjjohn2012/go,Charlesdong/go-1,polyverse-security/go,ifagnosticism/go,lihuanghai/go,jacobxk/go,suncycheng/go,yuhengye/go,sndnvaps/go,b54898533/go,devpadawan/go,yasarkunduz/go,jefby/go,NichoZhang/go,mdp/go,RBEGamer/go,wangfakang/go-1,cyberroadie/go,snowsnail/go,albertjin/golang-go,stormltf/go,jacobhaven/go,Young55555/go,Samurais/go,Badredapple/go,arschles/golang-go,JioCloud/go,dkolbly/go,cookerzhu/go,andrewchambers/go,jasonxiong/go,sndnvaps/go,monetate/go,zcwfeng/go,jonasi/go,cookerzhu/go,jonathanmarvens/go,cnbin/go,sndnvaps/go,baiyunping333/go,skotti/go,famorted/go,Samurais/go,alash3al/go,vishsingh/go,sndnvaps/go,dgnorton/go,constantine001/go,arschles/go-1,Endika/go,fjballest/golang,ImJasonH/go,monetate/go,lihuanghai/go,deft-code/go,jonahglover/go,sosop/go,CiscoCloud/go,WIZARD-CXY/go,derekmarcotte/go,CAFxX/go,ErikDubbelboer/go,likesea/go,Endika/go,roth1002/go,parkdy/go,devpadawan/go,arschles/golang-go,youprofit/go,vsekhar/elastic-go,jacobsa/go,ganboing/go-esx,dgnorton/go,ichu501/go,samanalysis/go,cyberroadie/go,golang/go,xinhuang327/go,yuhengye/go,ImJasonH/go,gohin/go,ganboing/go-esx,WIZARD-CXY/go,CiscoCloud/go,willjunspecial/go,Endika/go,dgnorton/go,akutz/go,zouchao2010/go,cloudrain21/go,Pulgafree/go,fjballest/golang,dterei/go,XuYunnan/go,chinanjjohn2012/go,shines77/go,willjunspecial/go,ganboing/go-esx,mikekap/go,Samurais/go,Stan-Lin-/go,famorted/go,deft-code/go,ObjectiveJoe/go,jasonxiong/go,CiscoCloud/go,AALEKH/go,roth1002/go,CiscoCloud/go,deft-code/go,ObjectiveJoe/go,CAFxX/go,alex-zhang/go,dterei/go,pgmreddy/go,XuYunnan/go,mbrukman/go,Young55555/go,derekmarcotte/go,likesea/go,NunoEdgarGub1/go,malvira/go,dkolbly/go,mdp/go,dafyddcrosby/go,xujianhai/go,Charlesdong/go-1,Cofyc/go,zouchao2010/go,GeorgiCodes/go,joshsammut/go,gohin/go,zcwfeng/go,monetate/go,pgmreddy/go,deft-code/go,vanloswang/go,zouchao2010/go,xiaobodu/go,greyhwndz/go,vsdutka/go,odeke-em/go,cyberroadie/go,GeorgiCodes/go,shines77/go,cookerzhu/go,goodlang/good,alex-zhang/go,xiuzhifu/go,cloudflare/go,vsdutka/go,cyberroadie/go,Jordanzuo/go,ObjectiveJoe/go,cainiaocome/go,dkolbly/go,shines77/go,Badredapple/go,polyverse-security/go,akutz/go,momchil-velikov/go,Endika/go,zcwfeng/go,christopher-henderson/Go,jonathanmarvens/go,josharian/go,stormltf/go,linux-on-ibm-z/go,CAFxX/go,likesea/go,rentongzhang/go,JioCloud/go,dpatel06/go,skotti/go,agaurav/go,nawawi/go,zcwfeng/go,andrewchambers/go,jacobxk/go,mgyenik/go,RBEGamer/go,g522342435/go,malvira/go,gdey/go,mgyenik/go,danielsoro/go,cnbin/go,shines77/go,donnel6809/go,cloudflare/go,honsiorovskyi/go,CAFxX/go,dterei/go,rachtsingh/gogojuice,rachtsingh/gogojuice,dterei/go,cloudrain21/go,AALEKH/go,Stan-Lin-/go,XuYunnan/go,Endika/go,dpatel06/go,monetate/go,xiuzhifu/go,Pulgafree/go,CarterTsai/go,devpadawan/go,parkdy/go,skatsuta/go,jacobsa/go,arschles/go-1,RBEGamer/go,agaurav/go,theass/go,gohin/go,likesea/go,CodyGuo/go,CodyGuo/go,willjunspecial/go,goodlang/good,vsekhar/elastic-go,NichoZhang/go,vishsingh/go,samanalysis/go,rentongzhang/go,ErikDubbelboer/go,myPublicGit/go,linux-on-ibm-z/go,ericsnowcurrently/go,zcwfeng/go,snowsnail/go,zcwfeng/go,xinhuang327/go,lihuanghai/go,jdhenke/go,undergrowthlinear/go,rachtsingh/gogojuice,mdp/go,famorted/go,monetate/go,willjunspecial/go,rachtsingh/gogojuice,honsiorovskyi/go,NunoEdgarGub1/go,Samurais/go,cainiaocome/go,jmptrader/go,sosop/go,donnel6809/go,theass/go,akutz/go,miolini/go,kim-racktop/go,xiaobodu/go,fjballest/golang,CodyGuo/go,yangzhongj/go,yasarkunduz/go,dterei/go,zcwfeng/go,arschles/go-1,jameskumar/go,greyhwndz/go,binarycrusader/go,sndnvaps/go,ichu501/go,honsiorovskyi/go,chinanjjohn2012/go,shazow/go,cloudrain21/go,fjballest/golang,devpadawan/go,mbrukman/go,ImJasonH/go,golang/go,greyhwndz/go,cainiaocome/go,kim-racktop/go,deft-code/go,kevinc0825/go,dkolbly/go,jdeng/go,theif519/go,golang/go,Badredapple/go,roth1002/go,mgyenik/go,goodlang/good,g522342435/go,jonasi/go,uileyar/go,xinhuang327/go,wangfakang/go-1,jacobxk/go,Stan-Lin-/go,youprofit/go,agaurav/go,cloudrain21/go,alash3al/go,honsiorovskyi/go,JioCloud/go,xiuzhifu/go,fjballest/golang,skotti/go,momchil-velikov/go,ifagnosticism/go,qskycolor/go,golang/go,dterei/go,cnbin/go,jmptrader/go,XuYunnan/go,akutz/go,jonathanmarvens/go,jonasi/go,vanloswang/go,Charlesdong/go-1,monetate/go,shines77/go,mwhudson/go,jacobsa/go,jdeng/go,kevinc0825/go,ganboing/go-esx,NichoZhang/go,jacobhaven/go,slavau/go,jacobsa/go,ErikDubbelboer/go,jonahglover/go,slavau/go,danycoro/go,jacobsa/go,honsiorovskyi/go,jdhenke/go,nawawi/go,mikekap/go,cyberroadie/go,shazow/go,devpadawan/go,parkdy/go,beealone/go,myPublicGit/go,vsekhar/elastic-go,mwhudson/go,yasarkunduz/go,samanalysis/go,kevinc0825/go,kakuhiroshi/go,alash3al/go,danielsoro/go,Endika/go,myPublicGit/go,shishkander/go,Samurais/go,binarycrusader/go,alex-zhang/go,famorted/go,andrewchambers/go,qskycolor/go,cloudrain21/go,pgmreddy/go,deft-code/go,josharian/go,g522342435/go,jonathanmarvens/go,andrewchambers/go,skotti/go,Young55555/go,ErikDubbelboer/go,alex-zhang/go,jonahglover/go,jacobhaven/go,samanalysis/go,Cofyc/go,danycoro/go,binarycrusader/go,baiyunping333/go,baiyunping333/go,akutz/go,xujianhai/go,theass/go,Charlesdong/go-1,GeorgiCodes/go,danycoro/go,cloudflare/go,linux-on-ibm-z/go,mwhudson/go,jasonxiong/go,jdhenke/go,malvira/go,leeric92/go,samanalysis/go,GeorgiCodes/go,skatsuta/go,donnel6809/go,odeke-em/go,zhangg/go,xujianhai/go,Jordanzuo/go,jasonxiong/go,NichoZhang/go,jacobxk/go,suncycheng/go,ericsnowcurrently/go,g522342435/go,xiaobodu/go,xujianhai/go,yasarkunduz/go,uileyar/go,Jordanzuo/go,albertjin/golang-go,jdhenke/go,vanloswang/go,CAFxX/go,yangzhongj/go,undergrowthlinear/go,derekmarcotte/go,pgmreddy/go,famorted/go,devpadawan/go,constantine001/go,jmptrader/go,XuYunnan/go,mbrukman/go,sndnvaps/go,Stan-Lin-/go,yangzhongj/go,jacobsa/go,jameskumar/go,springning/go,gdey/go,gdey/go,dgnorton/go,nawawi/go,constantine001/go,lihuanghai/go,qskycolor/go,skatsuta/go,josharian/go,nawawi/go,derekmarcotte/go,roth1002/go,beealone/go,famorted/go,samanalysis/go,binarycrusader/go,fjballest/golang,snowsnail/go,odeke-em/go,Pulgafree/go,willjunspecial/go,sosop/go,theif519/go,jacobhaven/go,pgmreddy/go,malvira/go,xinhuang327/go,Samurais/go,derekmarcotte/go,jonathanmarvens/go,NichoZhang/go,constantine001/go,ifagnosticism/go,andrewchambers/go,danycoro/go,odeke-em/go,xiaobodu/go,AALEKH/go,youprofit/go,Jordanzuo/go,donnel6809/go,alex-zhang/go,Cofyc/go,b54898533/go,linux-on-ibm-z/go,wangfakang/go-1,rentongzhang/go,ichu501/go,chinanjjohn2012/go,nakedgc/go,dafyddcrosby/go,andrewchambers/go,yangzhongj/go,xiuzhifu/go,zhangg/go,vishsingh/go,ericsnowcurrently/go,zouchao2010/go,sinuos/go,suncycheng/go,parkdy/go,Charlesdong/go-1,deft-code/go,skotti/go,codestation/go,codestation/go,Endika/go,golang/go,uileyar/go,AALEKH/go,arschles/go-1,snowsnail/go,ifagnosticism/go,theif519/go,gohin/go,rentongzhang/go,vishsingh/go,cloudflare/go,CarterTsai/go,b54898533/go,parkdy/go,4ad/go,andrewchambers/go,Badredapple/go,kim-racktop/go,kevinc0825/go,mdp/go,mgyenik/go,pgmreddy/go,uileyar/go,springning/go,baiyunping333/go,kim-racktop/go,springning/go,jefby/go,roth1002/go,jonahglover/go,lihuanghai/go,akutz/go,jdeng/go,jacobxk/go,albertjin/golang-go,arschles/go-1,theass/go,dpatel06/go,jmptrader/go,greyhwndz/go,mikekap/go,skotti/go,ericsnowcurrently/go,yasarkunduz/go,fjballest/golang,jacobxk/go,xinhuang327/go,ericsnowcurrently/go,vsekhar/elastic-go,codestation/go,jdeng/go,skatsuta/go,XuYunnan/go,cainiaocome/go,kim-racktop/go,alex-zhang/go,zouchao2010/go,rachtsingh/gogojuice,b54898533/go,CodyGuo/go,codestation/go,parkdy/go,RBEGamer/go,danycoro/go,golang/go,Samurais/go,Pulgafree/go,jmptrader/go,mwhudson/go,honsiorovskyi/go,greyhwndz/go,dafyddcrosby/go,shishkander/go,slavau/go,vishsingh/go,jameskumar/go,mwhudson/go,yangzhongj/go,momchil-velikov/go,linux-on-ibm-z/go,RBEGamer/go,springning/go,pgmreddy/go,beealone/go,jonahglover/go,mbrukman/go,XuYunnan/go,undergrowthlinear/go,leeric92/go,Samurais/go,CarterTsai/go,constantine001/go,jonasi/go,shishkander/go,miolini/go,leeric92/go,cnbin/go,sndnvaps/go,gdey/go,jasonxiong/go,zhangg/go,Stan-Lin-/go,cookerzhu/go,alash3al/go,GeorgiCodes/go,WIZARD-CXY/go,jameskumar/go,constantine001/go,ifagnosticism/go,jdhenke/go,binarycrusader/go,jacobhaven/go,codestation/go,snowsnail/go,sosop/go,jefby/go,xiuzhifu/go,arschles/golang-go,agaurav/go,qskycolor/go,vsdutka/go,snowsnail/go,Charlesdong/go-1,mikekap/go,odeke-em/go,stormltf/go,sosop/go,xiuzhifu/go,theass/go,baiyunping333/go,ImJasonH/go,rentongzhang/go,zouchao2010/go,jacobsa/go,roth1002/go,NunoEdgarGub1/go,lihuanghai/go,derekmarcotte/go,skotti/go,lihuanghai/go,kevinc0825/go,albertjin/golang-go,devpadawan/go,ericsnowcurrently/go,4ad/go,arschles/golang-go,ganboing/go-esx,jefby/go,momchil-velikov/go,parkdy/go,agaurav/go,JioCloud/go,sosop/go,b54898533/go,cyberroadie/go,binarycrusader/go,slavau/go,dkolbly/go,joshsammut/go,arschles/golang-go,mbrukman/go,Cofyc/go,sinuos/go,yuhengye/go,deft-code/go,willjunspecial/go,ErikDubbelboer/go,rentongzhang/go,Stan-Lin-/go,codestation/go,jacobxk/go,jasonxiong/go,ImJasonH/go,ImJasonH/go,malvira/go,xiaobodu/go,alex-zhang/go,kakuhiroshi/go,lihuanghai/go,dgnorton/go,Jordanzuo/go,rachtsingh/gogojuice,vsekhar/elastic-go,wangfakang/go-1,AALEKH/go,sosop/go,xujianhai/go,honsiorovskyi/go,uileyar/go,yuhengye/go,likesea/go,shines77/go,uileyar/go,leeric92/go,cloudflare/go,gdey/go,myPublicGit/go,g522342435/go,yuhengye/go,shishkander/go,momchil-velikov/go,josharian/go,Jordanzuo/go,jonasi/go,ErikDubbelboer/go,beealone/go,yangzhongj/go,ganboing/go-esx,skatsuta/go,nawawi/go,ObjectiveJoe/go,famorted/go,momchil-velikov/go,snowsnail/go,WIZARD-CXY/go,mbrukman/go,agaurav/go,mbrukman/go,ericsnowcurrently/go,dkolbly/go,miolini/go,zcwfeng/go,CodyGuo/go,ganboing/go-esx,goodlang/good,polyverse-security/go,Badredapple/go,danielsoro/go,shazow/go,dpatel06/go,ifagnosticism/go,jefby/go,slavau/go,xiuzhifu/go,codestation/go,cnbin/go,mgyenik/go,CiscoCloud/go,undergrowthlinear/go,Cofyc/go,dkolbly/go,kakuhiroshi/go,skatsuta/go,vanloswang/go,sinuos/go,mdp/go,Endika/go,GeorgiCodes/go,jonasi/go,stormltf/go,goodlang/good,4ad/go,skotti/go,qskycolor/go,sinuos/go,malvira/go,jonahglover/go,GeorgiCodes/go,kakuhiroshi/go,Stan-Lin-/go,samanalysis/go,nawawi/go,xiaobodu/go,stormltf/go,willjunspecial/go,dpatel06/go,AALEKH/go,cookerzhu/go,agaurav/go,Charlesdong/go-1,Pulgafree/go,myPublicGit/go,springning/go,slavau/go,Charlesdong/go-1,jasonxiong/go,albertjin/golang-go,beealone/go,ImJasonH/go,zhangg/go,myPublicGit/go,g522342435/go,shazow/go,Cofyc/go,goodlang/good,Young55555/go,dafyddcrosby/go,vsekhar/elastic-go,mgyenik/go,momchil-velikov/go,vanloswang/go,suncycheng/go,WIZARD-CXY/go,undergrowthlinear/go,ganboing/go-esx,cloudflare/go,famorted/go,slavau/go,jmptrader/go,vsekhar/elastic-go,nakedgc/go,kim-racktop/go,mbrukman/go,ichu501/go,nakedgc/go,4ad/go,shishkander/go,josharian/go,yangzhongj/go,snowsnail/go,nakedgc/go,CiscoCloud/go,Jordanzuo/go,chinanjjohn2012/go,4ad/go,Stan-Lin-/go,odeke-em/go,NichoZhang/go,mikekap/go,slavau/go,roth1002/go,alash3al/go,jdhenke/go,yasarkunduz/go,dpatel06/go,zhangg/go,wangfakang/go-1,jacobhaven/go,alex-zhang/go,likesea/go,jacobhaven/go,ErikDubbelboer/go,joshsammut/go,beealone/go,pgmreddy/go,stormltf/go,baiyunping333/go,cyberroadie/go,constantine001/go,polyverse-security/go,youprofit/go,andrewchambers/go,monetate/go,danycoro/go,cainiaocome/go,vanloswang/go,binarycrusader/go,dterei/go,kakuhiroshi/go,miolini/go,sinuos/go,nawawi/go,youprofit/go,danielsoro/go,greyhwndz/go,joshsammut/go,chinanjjohn2012/go,jdeng/go,cnbin/go,arschles/golang-go,Badredapple/go,Cofyc/go,gdey/go,xinhuang327/go,jdeng/go,agaurav/go,g522342435/go,beealone/go,gohin/go,polyverse-security/go,josharian/go,jonahglover/go,devpadawan/go,linux-on-ibm-z/go,springning/go,JioCloud/go,cloudflare/go,xinhuang327/go,Badredapple/go,kim-racktop/go,danielsoro/go,theass/go,dafyddcrosby/go,ifagnosticism/go,alash3al/go,jdeng/go,alash3al/go,youprofit/go,miolini/go,cainiaocome/go,cloudrain21/go,baiyunping333/go,Pulgafree/go,suncycheng/go,mikekap/go,skatsuta/go,XuYunnan/go,miolini/go,donnel6809/go,jonathanmarvens/go,polyverse-security/go,ObjectiveJoe/go,donnel6809/go,gdey/go,Cofyc/go,donnel6809/go,sndnvaps/go,kevinc0825/go,undergrowthlinear/go,CAFxX/go,dafyddcrosby/go,kakuhiroshi/go,dterei/go,leeric92/go,nawawi/go,zouchao2010/go,mgyenik/go,arschles/go-1,xujianhai/go,NunoEdgarGub1/go,b54898533/go,greyhwndz/go,Badredapple/go,yuhengye/go,suncycheng/go,JioCloud/go,shazow/go,dgnorton/go,vsdutka/go,arschles/golang-go,theif519/go,jmptrader/go,gohin/go,4ad/go,jacobsa/go,stormltf/go,cookerzhu/go,cloudrain21/go,akutz/go,likesea/go,myPublicGit/go,gohin/go,cainiaocome/go,zhangg/go,polyverse-security/go,ObjectiveJoe/go,dpatel06/go,kevinc0825/go,sosop/go,qskycolor/go,Young55555/go,mwhudson/go,NunoEdgarGub1/go,yasarkunduz/go,jasonxiong/go,GeorgiCodes/go,shazow/go,Young55555/go,ichu501/go,danycoro/go,jacobhaven/go,dgnorton/go,jonathanmarvens/go,jefby/go,mwhudson/go,CodyGuo/go,fjballest/golang,vsekhar/elastic-go,donnel6809/go,roth1002/go,wangfakang/go-1,CarterTsai/go,derekmarcotte/go,leeric92/go,theass/go,sinuos/go,vishsingh/go,CAFxX/go,CiscoCloud/go,wangfakang/go-1,b54898533/go,derekmarcotte/go,jonasi/go,mikekap/go,NunoEdgarGub1/go,greyhwndz/go,jdhenke/go,josharian/go,JioCloud/go,nakedgc/go,rachtsingh/gogojuice,shines77/go,samanalysis/go,kevinc0825/go,gohin/go,nakedgc/go,youprofit/go,ImJasonH/go,cookerzhu/go,willjunspecial/go,binarycrusader/go,AALEKH/go,joshsammut/go,undergrowthlinear/go,shazow/go,b54898533/go,dkolbly/go,RBEGamer/go,odeke-em/go,codestation/go,yuhengye/go,xiaobodu/go,theif519/go,alash3al/go,akutz/go,springning/go,dafyddcrosby/go,RBEGamer/go,jacobxk/go,albertjin/golang-go,jdeng/go,zouchao2010/go,RBEGamer/go,Pulgafree/go,uileyar/go,jmptrader/go,Young55555/go,polyverse-security/go,jameskumar/go,honsiorovskyi/go,chinanjjohn2012/go,kakuhiroshi/go,AALEKH/go,momchil-velikov/go,CarterTsai/go,rachtsingh/gogojuice,undergrowthlinear/go,shines77/go,ichu501/go,ichu501/go,CodyGuo/go,vsdutka/go,xiuzhifu/go,arschles/golang-go,CAFxX/go,jonasi/go,vanloswang/go,JioCloud/go,sinuos/go,malvira/go,nakedgc/go,cnbin/go,WIZARD-CXY/go,josharian/go,xiaobodu/go,Young55555/go,sinuos/go,mwhudson/go,parkdy/go,jonathanmarvens/go,vsdutka/go,CodyGuo/go,arschles/go-1,albertjin/golang-go,cainiaocome/go,miolini/go,mikekap/go,arschles/go-1,baiyunping333/go