Use cortex-a8 ldflags fix only for cortex-a8 devices
Merge JustArchi's build optimisations v3

For more info, visit
http://forum.xda-developers.com/showthread.php?t=2754997

Cherry-picked from
https://github.com/JustArchi/android_build/commit/1125f60a15194e08fdf18feacefb47696647e05b