Attached is the latest version.

It's very very slightly different from the version you suggested,
in the fact that I didn't create a local variable for the breakpoint
address, and stored it in *bp_addr directly.  I didn't see a real
purpose for having a local variable in this case.  I did create
a local variable for the nop instruction address, however. I found
that it did make things a little clearer for that one.

As before, I'm attaching two patches, the first being the last
version of the patch, and the second being the changes introduced
by this iteration.

Testec on mips-irix with no regression.  If we'd rather go with
AT_ENTRY_POINT instead, at least the patch is available here for
the record.

-- 
Joel