We only need it for MAX_ERRNO, and it's time we had somewhere to put the little assembler utility macros we've been putting off writing. Change-Id: I9354d2e0dc47c689296a34b5b229fc9ba75f1a83
(aarch64 kernels don't have these system calls.) Change-Id: I6f64075aa412f71520f2df71c3d69b647f91c1ca