[libunwind] libunwind update

[David Mosberger]

For those of you interested in monitoring the progress of libunwind: I
just checked in a fairly large changeset which adds support for
"remote" (cross-address space) unwinding.  The code also has been
cleaned up to enable cross-building.  The exact set of changes can
be found here:

        http://unwind.bkbits.net:8080/stable/address@hidden

Unless someone urgently wants to try this (and doesn't want to use
bitkeeper), I'll wait a bit before releasing libunwind v0.2.

        --david