That looks fine, though you should match `*-*-gnu*' for the configuration. Mark Kettenis is in charge of gdb for hurd and will take care of getting the fix put into gdb.
- Patches to GDB to make cross-compile friendly... Jeff Bailey
- Re: Patches to GDB to make cross-compile friendly... Roland McGrath
- Re: Patches to GDB to make cross-compile friendly... Mark Kettenis