Fix another compiler warning.
Fix another compiler warning.

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