build: Add support for PRODUCT_COPY_FILES_OVERRIDES

 * We may have a case where prebuilts need to be built from
   source instead based on an externalized config.
 * New directive takes a list of destination files to remove from
   PRODUCT_COPY_FILES so that other instructions can be supplied.

Change-Id: I7feff16440e54d1676ffddbbd96d5947efa43ede
build: Add QCOM target-specific config

 * Needed to support global DirectTract config on legacy targets
 * Let's also eliminate some boilerplate

Change-Id: I736c10a5e7e1f3d1e0de9e60f29b60add276f151

Conflicts:
	core/config.mk
qcom_utils: Update list of QCOM_BOARD_PLATFORMS

Add msm8226 (Moto G) and other upcoming platforms
Change-Id: Icf895cbcf86791ca800636a1c0893b3a905a27a0
build: Fix cflags for QC targets

Change-Id: I2281bec3afb4d80e80845718d880dc24ef7baf32
build: Cleanup CPU-specific optimizations

 * TARGET_ARCH_CPU_VARIANT was a Linaro thing. Now that Android
   introducted TARGET_CPU_VARIANT, we should use this instead.
 * Added CFLAGS for Krait and Scorpion after the cleanup.

Change-Id: Iafb40ecefa353a1169c22601be4ce80069c3f587