* util/grub-mkrelpath.c: New file.
* conf/common.rmk (bin_UTILITIES): Add grub-mkrelpath.
(grub_mkrelpath_SOURCES): New variable.
* include/grub/util/misc.h: New function prototype.
* util/misc.c (make_system_path_relative_to_its_root): New function.
* util/grub-mkconfig_lib.in (bindir): New variable.
(grub_mkrelpath): Likewise.
(make_system_path_relative_to_its_root): Use grub-mkrelpath.
* util/probe.c (probe): Make the file path relative to its root.
Change a info message to use the GRUB path. Enable again the
check if we can read the file with GRUB facilities.
* util/i386/pc/grub-setup.c (setup): Make core.img path relative
to its root.