[x86-64] Minor reformatting for GNU-style and use memset() in lieu of bzero().
[x86-64] Minor reformatting for GNU-style and use memset() in lieu of bzero().

SyndicateRogue/libunwind,mpercy/libunwind,androidarmv6/android_external_libunwind,evaautomation/libunwind,djwatson/libunwind,maltek/platform_external_libunwind,libunwind/libunwind,olibc/libunwind,yuyichao/libunwind,android-ia/platform_external_libunwind,wdv4758h/libunwind,fdoray/libunwind,zliu2014/libunwind-tilegx,bo-on-software/libunwind,dreal-deps/libunwind,martyone/libunwind,dropbox/libunwind,cms-externals/libunwind,joyent/libunwind,geekboxzone/lollipop_external_libunwind,wdv4758h/libunwind,wdv4758h/libunwind,geekboxzone/lollipop_external_libunwind,tronical/libunwind,rantala/libunwind,igprof/libunwind,atanasyan/libunwind,jrmuizel/libunwind,0xlab/0xdroid-external_libunwind,unkadoug/libunwind,atanasyan/libunwind,cloudius-systems/libunwind,dagar/libunwind,tony/libunwind,fillexen/libunwind,rogwfu/libunwind,maltek/platform_external_libunwind,geekboxzone/mmallow_external_libunwind,olibc/libunwind,igprof/libunwind,lat/libunwind,lat/libunwind,ehsan/libunwind,cloudius-systems/libunwind,yuyichao/libunwind,frida/libunwind,atanasyan/libunwind-android,atanasyan/libunwind-android,mpercy/libunwind,vegard/libunwind,0xlab/0xdroid-external_libunwind,frida/libunwind,dropbox/libunwind,tkelman/libunwind,rntz/libunwind,rogwfu/libunwind,adsharma/libunwind,cms-externals/libunwind,CyanogenMod/android_external_libunwind,Chilledheart/libunwind,djwatson/libunwind,fdoray/libunwind,fdoray/libunwind,Chilledheart/libunwind,krytarowski/libunwind,tronical/libunwind,ehsan/libunwind,vtjnash/libunwind,djwatson/libunwind,frida/libunwind,tkelman/libunwind,vtjnash/libunwind,zeldin/platform_external_libunwind,vtjnash/libunwind,project-zerus/libunwind,krytarowski/libunwind,dagar/libunwind,Keno/libunwind,DroidSim/platform_external_libunwind,CyanogenMod/android_external_libunwind,pathscale/libunwind,ehsan/libunwind,rogwfu/libunwind,dropbox/libunwind,dreal-deps/libunwind,dagar/libunwind,tronical/libunwind,androidarmv6/android_external_libunwind,tony/libunwind,zeldin/platform_external_libunwind,zeldin/platform_external_libunwind,tkelman/libunwind,rantala/libunwind,cloudius-systems/libunwind,DroidSim/platform_external_libunwind,android-ia/platform_external_libunwind,zliu2014/libunwind-tilegx,atanasyan/libunwind,project-zerus/libunwind,CyanogenMod/android_external_libunwind,dreal-deps/libunwind,adsharma/libunwind,martyone/libunwind,Keno/libunwind,Keno/libunwind,pathscale/libunwind,android-ia/platform_external_libunwind,rntz/libunwind,zliu2014/libunwind-tilegx,fillexen/libunwind,tony/libunwind,jrmuizel/libunwind,pathscale/libunwind,rantala/libunwind,geekboxzone/mmallow_external_libunwind,project-zerus/libunwind,vegard/libunwind,libunwind/libunwind,geekboxzone/lollipop_external_libunwind,androidarmv6/android_external_libunwind,0xlab/0xdroid-external_libunwind,fillexen/libunwind,evaautomation/libunwind,martyone/libunwind,evaautomation/libunwind,joyent/libunwind,SyndicateRogue/libunwind,unkadoug/libunwind,krytarowski/libunwind,SyndicateRogue/libunwind,DroidSim/platform_external_libunwind,cms-externals/libunwind,vegard/libunwind,joyent/libunwind,geekboxzone/mmallow_external_libunwind,unkadoug/libunwind,adsharma/libunwind,rntz/libunwind,mpercy/libunwind,libunwind/libunwind,olibc/libunwind,jrmuizel/libunwind,atanasyan/libunwind-android,Chilledheart/libunwind,lat/libunwind,bo-on-software/libunwind,bo-on-software/libunwind,igprof/libunwind,yuyichao/libunwind,maltek/platform_external_libunwind