- Add LDFLAGS_BLOB definitions
- Tweak kernel_thread for better code
- Fix vmlinux-armv.lds.in to prevent ld complaining about the
  architecture private flags.
(I'm not certain that the last item isn't a hole in some bug fix in
ld - this fix appears to work with every binutils I've found thus
far.  However, if this suspected bug gets fixed, we're going to have
to rethink how we combine binary objects into ELF objects.)