- Unhook usr.bin/uname from boot strap tools building, because it is not

- Unhook usr.bin/uname from boot strap tools building, because it is not
  used as boot strap tool at all.
- Add hw.machin_uname, which is "i386" on pc32(machine)/i386(cpu).  It is
  used by uname(1) -m option and uname(3), since most third party application
  understand "i386" much better than "pc32".  In uname(3), fallback to
  hw.machine, if hw.machine_uname does not exist, so we can stay compatible
  with old kernel which does not have hw.machine_uname.

Implementation-suggestions-from: dillon@
Approved-by: dillon@