[MIPSR6] Use C-coded string ops on mips32r6/mips64r6

The existing assembler code uses deprecated lwl/lwr/swl/swr ops.
Replacing those with misalignment-forgiving lw/sw ops may
involve careful performance tuning.

Change-Id: I47a042f7b22b87d7d52e46c29c44b1db1ba8b693
Only wipe TLS for user-supplied stacks.

Bug: 16667988
Change-Id: Id180ab2bc6713e1612386120a306db5bbf1d6046
Merge "Only wipe TLS for user-supplied stacks."
Merge "[MIPSR6] Use C-coded string ops on mips32r6/mips64r6"
Implement <sys/fsuid.h>.

Change-Id: I1e5e50444a1b5a430ba5b5d9b8b1d91219af5e92
Merge "Implement <sys/fsuid.h>."
Fix memchr with a zero length.

The memchr implementation for 64 bit fails if these conditions occur:

- The buffer is 32 byte aligned.
- The buffer contains the character in the first byte.
- The count sent in is zero.

The function should return NULL, but it's not.

Bug: 16676625
Change-Id: Iab33cc7a8b79920350c72f054dff0e0a3cde69ce
Merge "Fix memchr with a zero length."
Proper MB_CUR_MAX.

Previously this was hard coded to 4. This is only the case for UTF-8
locales.

As a side effect, this properly reports C.UTF-8 as the default locale
instead of C.

Change-Id: I7c73cc8fe6ffac61d211cd5f75287e36de06f4fc
Merge "Proper MB_CUR_MAX."