A while ago I reported problems locating source files that are specified
with relative paths in the compile line, detailed here:

http://sourceware.org/ml/gdb/2005-08/msg00066.html

Since then I've had a play around with the code and come up with the
attached diff which seems to solve the problem for me.  I couldn't see
any side effects as a result.

Can someone run a second set of eyes over this so that it can get
accepted to the mainline.

Thanks,
Craig.