bionic: update memmove for 32 bits atomic

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

Change-Id: I21cb77451270d061b32e3e2d2fda22e7e373b7ff
Fix build for x86. Remove duplicate mcmchr from Android.mk. Other implemented in arch-x86/x86.mk

Change-Id: I90a562960b214dd02b015d3e2715f711907ae9e8
Remove the dependency on the non-uapi __kernel_nlink_t.

The kernel doesn't have an nlink_t; it just uses the equivalent of
uint32_t. We already had a usable __nlink_t in the C library, so
let's just define our nlink_t in terms of __nlink_t, which is what
__nlink_t was meant for anyway.

Note that our struct stat just follows the kernel, and doesn't refer
to nlink_t anyway.

Change-Id: I6f51188d188fab975e286d6f8945fe746200b8d4
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_bionic into kk44