libc: Fix memchr inclusion

Change-Id: I6f374f16b08e19851a375a4abad3e8235f8da59c
libc: Fix memchr inclusion on scorpion

Change-Id: I0f4d31c85c8671be9790feab03469f89520763b7

Conflicts:
	libc/arch-arm/scorpion/scorpion.mk
libc: krait: Fix memmove half-word atomicity

In tailing case of less than 7, if even number of bytes are left, then
use half word load/store to make sure the whole routine is half-word
atomic

Change-Id: I54948ac050ff866986a7e144d4240652981ea87a
Add cfi stack unwinding back to cortex-a15 memcpy