GDB has a function to get real path of a file, gdb_realpath. Unfortunately,
that function is essentially a copy-paste of libiberty's lrealpath, with
the extra bonus that gdb_realpath *does not* have any Windows-specific
code. As result, GDB is not capable to simplify ".." in windows paths,
and among other problems, breakpoints set using full file names containing
".." will not work.

This patch makes GDB use libibery's lrealpath. OK?

- Volodya

       gdb/
       * utils.c (gdb_realpath): Use lrealpath.