* include/grub/emu/misc.h (grub_find_mount_point_from_dir)
(grub_find_zpool_from_mount_point): New function prototypes.
* kern/emu/getroot.c [HAVE_GETFSSTAT]: Move `<sys/mount.h>' to ...
* kern/emu/misc.c [HAVE_GETFSSTAT]: ... here.
* kern/emu/getroot.c (find_mount_point_from_dir): Move to ...
* kern/emu/misc.c (grub_find_mount_point_from_dir): ... this. Remove
`static' attribute.
* kern/emu/getroot.c (find_root_device_from_libzfs): Split code for
finding zpool from mount point into ...
* kern/emu/misc.c (grub_find_zpool_from_mount_point): ... this.
* kern/emu/misc.c (grub_make_system_path_relative_to_its_root): When
requested path is part of a ZFS pool, use
grub_find_zpool_from_mount_point() to detect its filesystem name,
and generate a path with `/fsname@path' syntax.
(grub_device_mapper_supported): New function.
* include/grub/emu/misc.h (grub_device_mapper_supported): Add
prototype.
* kern/emu/hostdisk.c (find_partition_start): Check whether
device-mapper is supported before trying to use it.
* util/deviceiter.c (grub_util_iterate_devices): Likewise.
return NULL for various reasons even if it has a maximum-length
buffer: for example, there might be a symlink loop, or the path
might exceed PATH_MAX. If this happens, return NULL.
