unwind: ignore memory mappings that have no PROT_EXEC bit set
unwind: ignore memory mappings that have no PROT_EXEC bit set

* unwind.c (build_mmap_cache): For each memory mapping being scanned,
save its PROT_EXEC bit and skip the mapping if it is not set.

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