UEFI support

[John Nemeth <jnemeth%cue.bc.ca@localhost>]

     As some people know, I've been working on adding UEFI support
to NetBSD.  The work on gpt(8) was only the first portion.  I have
other stuff that I will probably want to commit soon.  This raises
the question of where to commit it.  UEFI is found on the following
types of systems: ia64, x86 (both i386 and amd64), and aarch64
(64-bit ARM).  This means that it will be boot code for several
types of systems, and it will be the first quasi-MI bootcode.  As
such, there is no existing obvious place for where to put it.  Let
the bikeshedding begin...