Fix the detection of alt-network in dns resolver.

Used to determine proper A/AAAA record request.

bug:10132565
Change-Id: I7229f6672e879920a6fae58672cddd72db78546c

Conflicts:
	libc/netbsd/net/getaddrinfo.c
Add ssse3 implementation of __memcmp16.

__memcmp16 was missing in x86. Also added C-version for backward
compatibility. Added bionic test for __memcmp16 and for wmemcmp.

Change-Id: I33718441e7ee343cdb021d91dbeaf9ce2d4d7eb4
Signed-off-by: Alexander Ivchenko <alexander.ivchenko@intel.com>

Conflicts:
	libc/arch-x86/string/ssse3-memcmp3-new.S
	libc/arch-x86/string/ssse3-wmemcmp-atom.S
	libc/arch-x86/x86.mk

Conflicts:
	libc/arch-x86/x86.mk