unwind: cleanup build_mmap_cache
unwind: cleanup build_mmap_cache

* unwind.c (build_mmap_cache): Move local variables to the code branch
where they are used.  Check return code of sscanf and strdup.  Do not
treat unusual memory mappings as fatal errors.  Do not skip memory
mappings with path names starting with "[".

Saruta/strace,Infinitive-OS/platform_external_strace,Yu-AndroidM/android_external_strace,cuviper/strace,bigzz/strace_android,Distrotech/strace,YUPlayGodDev/platform_external_strace,geekboxzone/mmallow_external_strace,geekboxzone/mmallow_external_strace,Saruta/strace,MonkeyZZZZ/platform_external_strace,CyanogenMod/android_external_strace,cuviper/strace,android-ia/platform_external_strace,bnoordhuis/strace,geekboxzone/lollipop_external_strace,MonkeyZZZZ/platform_external_strace,geekboxzone/lollipop_external_strace,android-ia/platform_external_strace,geekboxzone/mmallow_external_strace,vrastogi/strace,android-ia/platform_external_strace,AOSP-YU/platform_external_strace,android-ia/platform_external_strace,geofft/strace,AOSP-YU/platform_external_strace,geekboxzone/mmallow_external_strace,kapdop/android_external_strace,android-ia/platform_external_strace,DirtyUnicorns/android_external_strace,geofft/strace,xin3liang/platform_external_strace,geofft/strace,DirtyUnicorns/android_external_strace,kapdop/android_external_strace,kapdop/android_external_strace,Distrotech/strace,YUPlayGodDev/platform_external_strace,Infinitive-OS/platform_external_strace,cuviper/strace,Distrotech/strace,TeamExodus/external_strace,lkundrak/strace,TeamExodus/external_strace,cuviper/strace,lkundrak/strace,DirtyUnicorns/android_external_strace,Saruta/strace,TeamExodus/external_strace,TeamExodus/external_strace,YUPlayGodDev/platform_external_strace,TeamExodus/external_strace,vrastogi/strace,geekboxzone/lollipop_external_strace,xin3liang/platform_external_strace,geekboxzone/lollipop_external_strace,DirtyUnicorns/android_external_strace,AOSP-YU/platform_external_strace,Saruta/strace,kapdop/android_external_strace,MonkeyZZZZ/platform_external_strace,Distrotech/strace,AOSP-YU/platform_external_strace,vrastogi/strace,Distrotech/strace,Infinitive-OS/platform_external_strace,CyanogenMod/android_external_strace,MonkeyZZZZ/platform_external_strace,bnoordhuis/strace,cuviper/strace,bnoordhuis/strace,CyanogenMod/android_external_strace,bigzz/strace_android,CyanogenMod/android_external_strace,Yu-AndroidM/android_external_strace,lkundrak/strace,Yu-AndroidM/android_external_strace,DirtyUnicorns/android_external_strace,geekboxzone/lollipop_external_strace,Infinitive-OS/platform_external_strace,bnoordhuis/strace,MonkeyZZZZ/platform_external_strace,bigzz/strace_android,geofft/strace,Yu-AndroidM/android_external_strace,Infinitive-OS/platform_external_strace,Saruta/strace,Yu-AndroidM/android_external_strace,geekboxzone/mmallow_external_strace,AOSP-YU/platform_external_strace,xin3liang/platform_external_strace,YUPlayGodDev/platform_external_strace,bigzz/strace_android,vrastogi/strace,CyanogenMod/android_external_strace,vrastogi/strace,lkundrak/strace,bigzz/strace_android,YUPlayGodDev/platform_external_strace,geofft/strace,xin3liang/platform_external_strace,kapdop/android_external_strace