* util/grub-mkrescue.in: Sync up with grub-install in terms of how
we handle finding grub-mkimage.  Default to finding grub-mkimage in
${bindir} with program_transform_name applied, and provide a
--grub-mkimage option to override this.
Fix build with non-GNU libcs.
* util/misc.c (canonicalize_file_name): Move to ...
* kern/emu/misc.c (canonicalize_file_name): ... here.  Needed by
grub_make_system_path_relative_to_its_root.