* util/hostdisk.c: Include `<grub/i18n.h>'.
(find_grub_drive): Use ARRAY_SIZE for map size calculation.
(make_device_name): Rewrite using asprintf.
(convert_system_partition_to_system_disk): Replace 0 with NULL.
(find_system_device): If a device is not found, generate one just
by reusing the OS path name.
(read_device_map): Make it permissible for device.map not to exist.