Large file support for grub-mkisofs.
* conf/common.rmk (grub_mkisofs_CFLAGS): Add `-D_FILE_OFFSET_BITS=64'.
* util/mkisofs/mkisofs.c (next_extent, last_extent)
(session_start): Upgrade type to `uint64_t'. Update all users.
* util/mkisofs/mkisofs.h: Include `<stdint.h>'.
(struct directory_entry): Upgrade type of `starting_block' and
`size' to `uint64_t'. Update all users.
(struct deferred): Remove unused structure.
(xfwrite): Upgrade type of `count' and `size' to `uint64_t'.
Update all users.
* util/mkisofs/tree.c (stat_filter, lstat_filter): Return -1 when
file is larger than `UINT32_MAX'.
* util/mkisofs/write.c (xfwrite): Upgrade type of `count' and
`size' to `uint64_t'. Update all users. Fix handling of fwrite()
return value.
(struct deferred_write): Upgrade type of `extent' and `size' to
`uint64_t'. Update all users.
(last_extent_written): Upgrade type to `uint64_t'. Update all
users.
(write_one_file): Upgrade type of `count' and `size' to `uint64_t'.
Update all users. Upgrade type of `remain' to `int64_t' and
`use' to `size_t'. Use error() to handle fread() errors.
(write_files): Rely on write_one_file() rather than calling
xfwrite() directly.
