To make things more concrete to what I was refering to in
http://sourceware.org/ml/gdb/2007-11/msg00138.html I've filed pr 2360,
and attached is an example fix.

I'm not sufficiently happy with it that I'd submit it RFA, but that's
mostly because of perceived objections to the use of xfullpath.  Maybe
the thing to do is write a canonicalizer like what is done in
cli-cmds.c:cd_command (and presumably move it to a more generic
place).

Suggestions?