This should fix a bug reported by Daniel when the source file is
compiled using absolute filenames.

        % gcc -c -o foo /path/to/foo.c

As Daniel reported, what happens in this case is that the compiler
puts the filename full path into the filename, and then leaves the
dirname empty.

2007-01-12  Joel Brobecker  <brobecker@adacore.com>

        * source.c (find_and_open_source): Try rewriting the source
        path inside filename if dirname is NULL.

Tested on x86-linux, no regression.
OK to apply?

Thanks,
-- 
Joel