Fix PTRACE_SINGLESTEP typo.
Fix PTRACE_SINGLESTEP typo.

Use correct spelling of PTRACE_SINGLESTEP symbol, so test suite
coverage works as intended.

Signed-off-by: Zachary T Welch <ed31003884a63125fcccb7c6499cbee2f4d64832@codesourcery.com>

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