Revert "Bring back Krait optimizations and more cflag tweaks"

This reverts commit bed2b5eac792ef4054f8e0bfaf4473ed397aefe3.
Revert "Global -0fast"

This reverts commit eecba90f0b5cf7c2c9a8da3b8f091231e34af879.
Revert "Clean up and reorganize all the build optimizations"

This reverts commit 717bd930c04050e7e449ff556dcbaab6dafe43f0.