Added audit.h from the kernel.

Just followed the recipe in I1ca996541d05b0d5927ab828a6ce49c09877ea01

Change-Id: I5713d9ce5ff62e310a694ecfbe21cad6577bcb4d
Provide glibc-compatible SYS_* aliases for the __NR_* constants.

This helps us remove another external/strace bionic hack.

Change-Id: I3e82c0d2fd27e479be98f096e05b666fd16f8eb3
Don't #define SYS_ constants unless they make sense for the current architecture.

Fixes the MIPS and x86 builds. strace tests whether syscalls
are supported using #ifdef of the appropriate SYS_ constant.

Change-Id: I90be118dc42abfdaf5b0f9b1e676e8601f55106e