Add compilation flags [2] (cherry-pick of FML optimizations)

O3, strict aliasing, better separation of ARM toolchains, LTO, C++11, etc.

Conflicts:
	core/combo/TARGET_linux-arm.mk
	core/combo/arch/arm/armv7-a-neon.mk
	core/combo/select.mk
	envsetup.sh

Change-Id: I5d43b9b2e54456bd9670e8d88b9870df4b39b288