I think this patch meets the requirements that Ian and others requested.
(I've put Ian in the CC: to get his reaction.)
I guess I think it would be OK to put this patch in without getting
everything else working, just so that it's not a moving target, but
that's arguable, and I have an obvious bias. So, what I'm hoping is
that Ian will say that the patch is OK, and indicate whether he thinks
we should put it in now, or wait until you have (a) the cfun stuff, and
(b) the MIPS bits all ready to go as well.