Add TARGET_GCC_VERSION

Default to 4.6, but can overwritten to something else in
prebuilts/gcc/$os/$arch/$arch-linux-android*-$ver

Change-Id: I16f99d642b8ff8e831d392261a0c536041107051
Extend the usage of TARGET_GCC_VERSION for gdb and arm-eabi-*.

In the future to upgrade the gcc version we just need to edit one
line in core/config.mk.

Change-Id: I01bb38c38f2388913bb7369aa4b2da480411dfbe
Define TARGET_GCC_VERSION in target specific make files.

So that GCC refresh can be performed in a target specific way.

Change-Id: I867e8b8fd671bef8c5af300e657a6da4fface032
Enable lunch command to pick up new toolchain version.

Otherwise the previously exported value will be sticky and the value
defined in the TARGET makefile is ignored.

Change-Id: Icdacb8c46034b8a24a9875b7596b31d00861512a
Specify -msse3 on host as on target.

Make the host and the target x86 build more uniform by using the same machine flags.
Its unlikely Android has ever been built on a machine without SSE3 support.

Bug: 8068608
Change-Id: I19635528b61bf2c6faf02c2e575b1d9bf8025d3a
ARMv7-A flags update
Use separate file for NEON targets, add TARGET_CPU_VARIANT (in line to AOSP), add Krait flags
avoid llvm complaining new flags
strict-aliasing and 03