Don't use an alternative stack for SIGSEGV & co.
Don't use an alternative stack for SIGSEGV & co.

This commit reverts most of c575766202773c858be0870c20cd495b722927c3, in
order to use back main stack for signal handling.

The main reason is that otherwise it is completely pointless that we do
a lot of efforts to print the stack trace on crash, and the content of
the stack and registers as well. Using an alternate stack broken this
feature completely.

colstrom/redis,citusdata/redis,oranagra/redis,PKRoma/redis,holstvoogd/redis,cloudrain21/redis,roth1002/redis,francischan714/redis,MasahikoSawada/redis,antirez/redis,mcanthony/redis,gongice/redis-3.0-annotated,devaos/redis,josephholsten/redis,maodeyi/redis_lua,riyan8250/redis,elkingtonmcb/redis,gilala/bjredis,fengshao0907/redis,wujf/redis,roth1002/redis,Instagram/redis,netroby/redis,machicao2013/redis-source-annotated,cloudrain21/redis,qiyang0221/redis,iandyh/redis,allengaller/redis,pietern/redis,xuzhezhaozhao/redis_reading,ouyangkongtong/redis,shshlzh/redis-3.0-annotated,kensou97/redis,msn217/redis-3.0-annotated,ouyangkongtong/redis,shreesundara/redis,jasonkying/redis,rogerlz/redis,PKRoma/redis,cloudrain21/redis,gilala/redis,j0hnma/hszredis,mumingv/redis,mingyaaaa/redis,soveran/redis,gaoxianglong/redis,cnbin/redis,miaoyc1989/redis-3.0-annotated,ErikDubbelboer/redis,StevenTsai/redis,huyuezheng/redis,GitHubMota/redis,seppo0010/rlite-server,tellapart/redis,honestme/redis,shshlzh/redis-3.0-annotated,0x55/redis-3.0-annotated,takeshineshiro/redis,NBSW/redis,AALEKH/redis,timothyohare/3rdPartySrc-redis,mengyou0304/redis,LongXQ/redis,wprice/redis,mpalmer/redis,spinlock/redis,mgk/redis,slfs007/mk-redis,holstvoogd/redis,Instagram/redis,saisai/redis,brg-liuwei/redis,CodeJuan/redis,AplayER/redis,flashbuckets/redis,ttuna/msot-redis,xlzhan/redis,yuhc/redis-benchmark-enhanced,ytjiang/redis,yossigo/redis,blackmady/redis,alenslan/redis,adamweixuan/redis-3.0-annotated,clamoriniere1A/redis,NBSW/redis,taoguan/redis,hgl888/redis,universsky/redis,yybirdcf/learn-redis,mengzhejin/RedisStudy,ErikDubbelboer/redis,blackmady/redis,buobao/redis-3.0-annotated,himoca/redis,yybirdcf/learn-redis,idning/redis,AALEKH/redis,programmecat/redis,haima-zju/redis-3.0-annotated,ton31337/redis,valdsJohn/redis,jackyan/redis,hgl888/redis,HunanTV/redis,wbailey5/redis,healerkx/redis,oranagra/redis,ChaosCoo/annotated_redis_source,gechong/redis-3.0-annotated,gilala/hbjredis,nilyang/redis-tdd-annotation,jacklee0810/annotated_redis_source,wuxiaowei907/annotated_redis_source,slfs007/mk-redis,nuxeh/redis,duanx/redis,cnbin/redis,pcarrier/redis,yossigo/redis,clamoriniere1A/redis,ReadCode/redis-3.0-annotated,timothyohare/3rdPartySrc-redis,dayuoba/redis,weizijun/redis,iandyh/redis,cusspvz/redis,pietern/redis,RepmujNetsik/redis,h0x91b/redis,j0hnma/hszredis,elkingtonmcb/redis,wenxueliu/redis_comment,atreeyang/redis,WorkingOfTimtohyZhang/redis-3.0-annotated,zczhuohuo/redis,alenslan/redis,dongqifan2/redis-3.0-annotated,AALEKH/redis,mcanthony/redis,slfs007/mk-redis,moonbingbing/redis-3.0-annotated,seppo0010/rlite-server,itamarhaber/redis,fengshao0907/annotated_redis_source,HeartSaVioR/redis,universsky/redis,himoca/redis,CodeJuan/redis,rogerlz/redis,rogerlz/redis,itamarhaber/redis,moonbingbing/redis-3.0-annotated,roth1002/redis,jingjidejuren/redis,huyuezheng/redis,0x20h/redis,wujf/redis,pmem/redis,supasate/redis,ksarch-saas/redis,duanx/redis,mpalmer/redis,maodeyi/redis_lua,gilala/bjredis,SummonY/redis,izhoujie/redis,qiyang0221/redis,sunlianqiang/redis-3.0-annotated,Aliceljm1/redis-3.0-annotated,thomasdarimont/redis,ituncle/redis,4396/redis,rogerchina/redis,jbochi/parallel_redis,onlymellb/redis-3.0-annotated,july2993/redis,itamarhaber/redis,csuhawk/redis,simplestbest/redis,pedigree/redis,wbailey5/redis,duanx/redis,Hailei/redis,CodeJuan/redis,MasahikoSawada/redis,pedigree/redis,buobao/redis-3.0-annotated,fengshao0907/redis-3.0-annotated,ReadCode/redis-3.0-annotated,rogerlz/redis,supasate/redis,HunanTV/redis,xuguruogu/redis,ttuna/msot-redis,mgk/redis,jacklee0810/redis-3.0-annotated,guker/redis,0x55/redis-3.0-annotated,jermnelson/redis,kensou97/redis,xuzhezhaozhao/redis_reading,Soledad89/redis,j0hnma/szredis,ouyangkongtong/redis,mrb/redis,gechong/redis-3.0-annotated,pcarrier/redis,HouKangkang/redis-3.0-annotated,jingjidejuren/redis,MOON-CLJ/redis,Aliceljm1/redis,hhli/redis,aim-for-better/redis,seppo0010/redis,yossigo/redis,0x20h/redis,tanghaodong25/redis,josiahcarlson/redis,rogerchina/redis,SyntaxStacks/redis,qiyang0221/redis,healerkx/redis,mumingv/redis-3.0-annotated,miaoyc1989/redis-3.0-annotated,tjschuck/redis,a-pavlov/redis,harrisonfeng/redis,Markgorden/redis,JoeWoo/redis,huangz1990/experiment-redis,oranagra/redis,gilala/redis,xujunhai1991/redis,a-pavlov/redis,hedisdb/hedis,wenxueliu/redis_comment,miaoyc1989/redis-3.0-annotated,GitHubMota/redis,soloestoy/redis,MSOpenTech/redis,MasahikoSawada/redis,PKRoma/redis,fengshao0907/redis,aluzzardi/redis,tjschuck/redis,xujunhai1991/redis,yuzhangjob/redis-3.0-annotated-unstable,elkingtonmcb/redis,GrimDerp/redis,rrsean/redis-3.0-annotated,takeshineshiro/redis,alenslan/redis,itamarhaber/redis,fengshao0907/redis,soloestoy/redis,onlymellb/redis-3.0-annotated,devaos/redis,YongMan/redis,mverrilli/redis,guker/redis,xuzhezhaozhao/redis_reading,ketor/redis,Hailei/redis,hedisdb/hedis,NBSW/redis,ituncle/redis,gilala/bjredis,hhli/redis,gechong/redis-3.0-annotated,allengaller/redis,dayuoba/redis,rouzier/redis,dongqifan2/redis-3.0-annotated,sunheehnus/redis,kensou97/redis,rouzier/redis,tellapart/redis,fengshao0907/redis-3.0-annotated,Wangyao14cyy/redis,cnbin/redis,splitice/redis,mingyaaaa/redis,nnog/redis,antirez/redis,thomasdarimont/redis,citusdata/redis,colstrom/redis,kmiku7/redis,darksideofthemoo/redis-histogram,linfangrong/redis,fengshao0907/annotated_redis_source,gilala/redis,ErikDubbelboer/redis,ituncle/redis,kaushik94/redis,arijitvt/redis,vincent-vivian-liu/redis,weizijun/redis,spinlock/redis,francischan714/redis,xujunhai1991/redis,Instagram/redis,supasate/redis,neomantra/redis,190235047/redis,Cisphyx/redis-websockets,pedigree/redis,wuxiaowei907/annotated_redis_source,antirez/redis,qiyang0221/redis,buobao/redis-3.0-annotated,guker/redis,raphaelfruneaux/redis,zhaobo1023/redis-3.0-annotated,narma/redis,moonbingbing/redis-3.0-annotated,Cisphyx/redis-websockets,StevenTsai/redis,sunlianqiang/redis-3.0-annotated,hawkchch/redis,soloestoy/redis,nilyang/redis-tdd-annotation,viongpanzi/annotated_redis_source,gilala/hbjredis,splitice/redis,ttuna/msot-redis,4396/redis,PradheepShrinivasan/redis,holstvoogd/redis,magastzheng/redis-3.0-annotated,soveran/redis,twskipper/redis,healerkx/redis,Aliceljm1/redis-3.0-annotated,josiahcarlson/redis,miaoyc1989/redis-3.0-annotated,xuguruogu/redis,whille/redis-3.0-annotated,AplayER/redis,GrimDerp/redis,huangz1990/experiment-redis,pcarrier/redis,MSOpenTech/redis,ncopa/redis,abhiklodh/redis,kaushik94/redis,j0hnma/szredis,drinkthere/redis-3.0-annotated,timothyohare/3rdPartySrc-redis,fengshao0907/redis,hgl888/redis,huangz1990/experiment-redis,tanghaodong25/redis,danny200309/annotated_redis_source,ton31337/redis,ChanningDuan/annotated_redis_source,ErikDubbelboer/redis,aluzzardi/redis,YuraLukashik/redis,spinlock/redis,jacklee0810/annotated_redis_source,SummonY/redis,z-fork/redis,ofirluzon/redis,abhiklodh/redis,fankeke/redis-3.0-annotated,zhcy/redis,gilala/hredis,msn217/redis-3.0-annotated,flashbuckets/redis,dayuoba/redis,hhli/redis,jermnelson/redis,ton31337/redis,seppo0010/rlite-server,gilala/hbjredis,supasate/redis,figoxu/annotated_redis_source,sunheehnus/redis,ksarch-saas/redis,zhoudayang/redis,ChaosCoo/annotated_redis_source,gspandy/annotated_redis_source,OmarQunsul/graph-redis,charsyam/redis,honestme/redis,programmecat/redis,jasonkying/redis,idning/redis,gilala/bjredis,whille/redis-3.0-annotated,haima-zju/redis-3.0-annotated,universsky/redis,YuraLukashik/redis,Soledad89/redis,PradheepShrinivasan/redis,gspandy/annotated_redis_source,zy416548283/redis-3.0-annotated,zhoudayang/redis,fengshao0907/redis-3.0-annotated,shining-yang/redis,RepmujNetsik/redis,190235047/redis,onlymellb/redis-3.0-annotated,janekmi/redis,jingjidejuren/redis,shining-yang/redis,valdsJohn/redis,wbailey5/redis,brg-liuwei/redis,AplayER/redis,spinlock/redis,vincent-vivian-liu/redis,shreesundara/redis,neomantra/redis,hornen/redis,hhli/redis,tanghaodong25/redis,ofirluzon/redis,mumingv/redis,atreeyang/redis,july2993/redis,j0hnma/hszredis,arijitvt/redis,jbochi/redis,dreamquster/redis,mengzhejin/RedisStudy,cusspvz/redis,mengyou0304/redis,nnog/redis,ipmobiletech/redis,yuzhangjob/redis-3.0-annotated-unstable,splitice/redis,Cisphyx/redis-websockets,ton31337/redis,narma/redis,jxwr/redis,jacklee0810/annotated_redis_source,thomasdarimont/redis,seppo0010/redis,jacklee0810/redis-3.0-annotated,weizijun/redis,josiahcarlson/redis,nnog/redis,jingjidejuren/redis,StevenTsai/redis,LongXQ/redis,davidradunz/redis,ouyangkongtong/redis,ituncle/redis,wenxueliu/redis_comment,hornen/redis,kmiku7/redis,july2993/redis,z-fork/redis,yossigo/redis,Aliceljm1/redis,mumingv/redis,zguangyu/redis,Cisphyx/redis-websockets,YuanZhewei/redis,SyntaxStacks/redis,mingyaaaa/redis,kensou97/redis,ofirluzon/redis,modulexcite/redis,seandsky/redis,itugs/redis,honestme/redis,yossigo/redis,saisai/redis,tidatida/annotated_redis_source,programmecat/redis,jxwr/redis,MasahikoSawada/redis,mrb/redis,ncopa/redis,rrsean/redis-3.0-annotated,HeartSaVioR/redis,h0x91b/redis,mumingv/redis-3.0-annotated,shreesundara/redis,harrisonfeng/redis,cloudrain21/redis,raphaelfruneaux/redis,yuhc/redis-benchmark-enhanced,harrisonfeng/redis,idning/redis,linfangrong/redis,MOON-CLJ/redis,mengyou0304/redis,pkdevbox/redis,mengzhejin/RedisStudy,Aliceljm1/redis-3.0-annotated,pkdevbox/redis,mcanthony/redis,PKRoma/redis,gspandy/annotated_redis_source,mgk/redis,Markgorden/redis,machicao2013/redis-source-annotated,taoguan/redis,GrimDerp/redis,pkdevbox/redis,ksarch-saas/redis,HeartSaVioR/redis,jbochi/redis,kaushik94/redis,wprice/redis,dramenk/annotated_redis_source,pmem/redis,wenxueliu/redis_comment,wangyikai/redis,oranagra/redis,mpalmer/redis,davidradunz/redis,a-pavlov/redis,josephholsten/redis,0x20h/redis,Sciumo/redis,ytjiang/redis,hornen/redis,tjschuck/redis,HunanTV/redis,Aaron1992/redis,nuxeh/redis,francischan714/redis,OmarQunsul/graph-redis,zhoudayang/redis,ncopa/redis,wujf/redis,zhaobo1023/redis-3.0-annotated,antirez/redis,OmarQunsul/graph-redis,tellapart/redis,ketor/redis,pkdevbox/redis,pmem/redis,allengaller/redis,huyuezheng/redis,maodeyi/redis_lua,huangz1990/annotated_redis_source,xuguruogu/redis,valdsJohn/redis,raphaelfruneaux/redis,YuraLukashik/redis,soveran/redis,ketor/redis,jackyan/redis,aluzzardi/redis,JoeWoo/redis,louisliangjun/redis,Sciumo/redis,adamweixuan/redis-3.0-annotated,linfangrong/redis,gilala/hredis,viongpanzi/annotated_redis_source,fankeke/redis-3.0-annotated,cusspvz/redis,huangz1990/redis-3.0-annotated,oranagra/redis,HunanTV/redis,gaoxianglong/redis,blackmady/redis,mverrilli/redis,mattsta/redis,janekmi/redis,yybirdcf/learn-redis,machicao2013/redis-source-annotated,guker/redis,hawkchch/redis,JoeWoo/redis,190235047/redis,z-fork/redis,jermnelson/redis,soloestoy/redis,zguangyu/redis,4396/redis,simplestbest/redis,huangz1990/redis-3.0-annotated,gongice/redis-3.0-annotated,nuxeh/redis,Sciumo/redis,csuhawk/redis,tidatida/annotated_redis_source,drinkthere/redis-3.0-annotated,wuyu201321060203/redis-3.0-annotated,xuguruogu/redis,wuxiaowei907/annotated_redis_source,Soledad89/redis,wuyu201321060203/redis-3.0-annotated,twskipper/redis,j0hnma/szredis,LongXQ/redis,gaoxianglong/redis,neomantra/redis,josiahcarlson/redis,0x55/redis-3.0-annotated,rouzier/redis,jxwr/redis,blackmady/redis,splitice/redis,modulexcite/redis,nuxeh/redis,spearhead-ea/redis,GitHubMota/redis,SyntaxStacks/redis,ramonsnir/redis,takeshineshiro/redis,magastzheng/redis-3.0-annotated,j0hnma/szredis,ytjiang/redis,hedisdb/hedis,sunheehnus/redis,brg-liuwei/redis,ttuna/msot-redis,gilala/hredis,OmarQunsul/graph-redis,mgk/redis,darksideofthemoo/redis-histogram,ctripcorp/redis,zhcy/redis,Aliceljm1/redis,itugs/redis,itugs/redis,kmiku7/redis,ChanningDuan/annotated_redis_source,figoxu/annotated_redis_source,Aaron1992/redis,netroby/redis,dreamquster/redis,modulexcite/redis,colstrom/redis,dramenk/annotated_redis_source,MOON-CLJ/redis,dreamquster/redis,fengshao0907/annotated_redis_source,atreeyang/redis,seandsky/redis,huangz1990/annotated_redis_source,xujunhai1991/redis,yuhc/redis-benchmark-enhanced,ipmobiletech/redis,himoca/redis,mverrilli/redis,mattsta/redis,unasm/redis-3.0-annotated,ncopa/redis,sunlianqiang/redis-3.0-annotated,aim-for-better/redis,shining-yang/redis,HouKangkang/redis-3.0-annotated,mverrilli/redis,louisliangjun/redis,xuzhezhaozhao/redis_reading,CodeJuan/redis,huangz1990/experiment-redis,ramonsnir/redis,tidatida/annotated_redis_source,0x20h/redis,mengzhejin/RedisStudy,soveran/redis,jbochi/redis,nilyang/redis-tdd-annotation,zczhuohuo/redis,Hailei/redis,citusdata/redis,dramenk/annotated_redis_source,Aliceljm1/redis,yuhc/redis-benchmark-enhanced,saisai/redis,darksideofthemoo/redis-histogram,izhoujie/redis,soloestoy/redis,harrisonfeng/redis,ctripcorp/redis,seppo0010/redis,unasm/redis-3.0-annotated,YongMan/redis,janekmi/redis,twskipper/redis,mumingv/redis-3.0-annotated,cnbin/redis,tellapart/redis,NBSW/redis,csuhawk/redis,wangyikai/redis,StevenTsai/redis,davidradunz/redis,twskipper/redis,gilala/hbjredis,roth1002/redis,ofirluzon/redis,ReadCode/redis-3.0-annotated,charsyam/redis,pietern/redis,iandyh/redis,ChanningDuan/annotated_redis_source,sunheehnus/redis,iandyh/redis,jackyan/redis,nilyang/redis-tdd-annotation,badboy/redis,Hailei/redis,davidradunz/redis,riyan8250/redis,jasonkying/redis,mingyaaaa/redis,mattsta/redis,ramonsnir/redis,spearhead-ea/redis,seppo0010/rlite-server,zhaobo1023/redis-3.0-annotated,jacklee0810/redis-3.0-annotated,190235047/redis,j0hnma/hszredis,thomasdarimont/redis,h0x91b/redis,Aaron1992/redis,simplestbest/redis,narma/redis,YuanZhewei/redis,citusdata/redis,yybirdcf/learn-redis,SyntaxStacks/redis,kmiku7/redis,ytjiang/redis,WorkingOfTimtohyZhang/redis-3.0-annotated,JoeWoo/redis,Wangyao14cyy/redis,vincent-vivian-liu/redis,PKRoma/redis,itugs/redis,josephholsten/redis,pedigree/redis,netroby/redis,weizijun/redis,GitHubMota/redis,louisliangjun/redis,july2993/redis,hedisdb/hedis,flashbuckets/redis,abhiklodh/redis,darksideofthemoo/redis-histogram,xlzhan/redis,hgl888/redis,pmem/redis,zhiliaoniu/redis,izhoujie/redis,unasm/redis-3.0-annotated,Aaron1992/redis,shining-yang/redis,mrb/redis,mcanthony/redis,aluzzardi/redis,ctripcorp/redis,zy416548283/redis-3.0-annotated,mengyou0304/redis,ipmobiletech/redis,vincent-vivian-liu/redis,valdsJohn/redis,Markgorden/redis,YongMan/redis,zguangyu/redis,clamoriniere1A/redis,wangyikai/redis,devaos/redis,aim-for-better/redis,yuzhangjob/redis-3.0-annotated-unstable,allengaller/redis,rrsean/redis-3.0-annotated,seandsky/redis,zy416548283/redis-3.0-annotated,nnog/redis,gaoxianglong/redis,jbochi/parallel_redis,fankeke/redis-3.0-annotated,MSOpenTech/redis,PradheepShrinivasan/redis,wangyikai/redis,flashbuckets/redis,PradheepShrinivasan/redis,jasonkying/redis,kaushik94/redis,adamweixuan/redis-3.0-annotated,timothyohare/3rdPartySrc-redis,honestme/redis,pcarrier/redis,hawkchch/redis,louisliangjun/redis,rogerchina/redis,dayuoba/redis,spearhead-ea/redis,Soledad89/redis,huyuezheng/redis,taoguan/redis,seppo0010/redis,duanx/redis,takeshineshiro/redis,modulexcite/redis,aim-for-better/redis,zczhuohuo/redis,mumingv/redis,zhiliaoniu/redis,ChaosCoo/annotated_redis_source,badboy/redis,zhcy/redis,xlzhan/redis,Sciumo/redis,ksarch-saas/redis,charsyam/redis,gongice/redis-3.0-annotated,4396/redis,badboy/redis,izhoujie/redis,danny200309/annotated_redis_source,alenslan/redis,zguangyu/redis,elkingtonmcb/redis,RepmujNetsik/redis,HouKangkang/redis-3.0-annotated,neomantra/redis,wujf/redis,danny200309/annotated_redis_source,MSOpenTech/redis,wprice/redis,wuyu201321060203/redis-3.0-annotated,xlzhan/redis,YuraLukashik/redis,devaos/redis,h0x91b/redis,gilala/redis,machicao2013/redis-source-annotated,0x55/redis-3.0-annotated,mrb/redis,simplestbest/redis,WorkingOfTimtohyZhang/redis-3.0-annotated,LongXQ/redis,healerkx/redis,holstvoogd/redis,GrimDerp/redis,rogerchina/redis,ctripcorp/redis,YongMan/redis,badboy/redis,pietern/redis,ttuna/msot-redis,janekmi/redis,charsyam/redis,neomantra/redis,zhcy/redis,a-pavlov/redis,cusspvz/redis,atreeyang/redis,shreesundara/redis,taoguan/redis,rouzier/redis,hawkchch/redis,arijitvt/redis,whille/redis-3.0-annotated,tzq668766/redis-3.0-annotated,figoxu/annotated_redis_source,HeartSaVioR/redis,arijitvt/redis,universsky/redis,clamoriniere1A/redis,YuanZhewei/redis,AplayER/redis,haima-zju/redis-3.0-annotated,brg-liuwei/redis,ofirluzon/redis,RepmujNetsik/redis,Wangyao14cyy/redis,shshlzh/redis-3.0-annotated,SummonY/redis,tzq668766/redis-3.0-annotated,hornen/redis,drinkthere/redis-3.0-annotated,idning/redis,wbailey5/redis,charsyam/redis,tanghaodong25/redis,YuanZhewei/redis,linfangrong/redis,jbochi/parallel_redis,Wangyao14cyy/redis,jackyan/redis,shshlzh/redis-3.0-annotated,dreamquster/redis,csuhawk/redis,colstrom/redis,zhiliaoniu/redis,viongpanzi/annotated_redis_source,tzq668766/redis-3.0-annotated,huangz1990/redis-3.0-annotated,saisai/redis,seandsky/redis,msn217/redis-3.0-annotated,dongqifan2/redis-3.0-annotated,francischan714/redis,wuyu201321060203/redis-3.0-annotated,gilala/hredis,zhoudayang/redis,Markgorden/redis,zhiliaoniu/redis,netroby/redis,z-fork/redis,MSOpenTech/redis,magastzheng/redis-3.0-annotated,huangz1990/annotated_redis_source,AALEKH/redis,abhiklodh/redis,SummonY/redis,ipmobiletech/redis,wprice/redis,zczhuohuo/redis,riyan8250/redis,mpalmer/redis,tjschuck/redis,programmecat/redis,riyan8250/redis