Revert "Remove harmful attempts to be helpful in pthread_mutex functions."

This reverts commit 53f15d0325feeaf7e58dc79fce4ddf55e0a64b7a.

Change-Id: Ia17c84492fade46eea5ff872e602dfe024ff55c4
Import memchr implementation from cortex-strings for Cortex A15

Benchmarks on a Nexus 10 have shown the cortex-strings implementation
of memchr to be 60%-70% faster (depending on input)

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>

Change-Id: I72b119905234570e54068375e5c3593d0647c67c
libc: Fix memchr inclusion

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

Change-Id: I0f4d31c85c8671be9790feab03469f89520763b7
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
bionic: update memmove for 32 bits atomic

When src/dst are 32bits aligned, the updated memmove will guarantee
32bits atomic.

Change-Id: I21cb77451270d061b32e3e2d2fda22e7e373b7ff