Adding a MACHINE_ARCH note

[Andrew Turner]

On Tue, 9 Jul 2013 08:19:46 -0600
Warner Losh <imp at bsdimp.com> wrote:
> I thought that the ELF headers gave us all the data we needed to know
> how things were built...

It will tell us if it was for e.g. an ARM or MIPS ELF file, but I'm not
sure how we can tell the difference between an arm and an armv6 ELF.

With armv6 there are a few changes in the userland/kernel
interface, e.g. reading the thread local storage pointer is different
such that an armv6 static binary would not run on an ARMv5 core as it
uses newer instructions.

Andrew