(struct map_iterator): Add members "buf_size", "buf", and "buf_end". (maps_init): Try to mmap() a one-page buffer and, if successful, 	initialize the new map_iterator members based on it. (maps_next): If the one-page buffer is available, use it to read 	/proc/PID/maps.  This avoids expensive lseek() calls which, 	in the case of /proc lead to T(n) = O(n^2) behavior.
(struct map_iterator): Add members "buf_size", "buf", and "buf_end".
(maps_init): Try to mmap() a one-page buffer and, if successful,
	initialize the new map_iterator members based on it.
(maps_next): If the one-page buffer is available, use it to read
	/proc/PID/maps.  This avoids expensive lseek() calls which,
	in the case of /proc lead to T(n) = O(n^2) behavior.

(Logical change 1.208)

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