(BACKUP_OPTION, DELETE_OPTION, EXCLUDE_OPTION, GROUP_OPTION,

(BACKUP_OPTION, DELETE_OPTION, EXCLUDE_OPTION, GROUP_OPTION,
MODE_OPTION, NEWER_MTIME_OPTION, NO_RECURSE_OPTION, NULL_OPTION,
OWNER_OPTION, POSIX_OPTION, PRESERVE_OPTION, RECORD_SIZE_OPTION,
RSH_COMMAND_OPTION, SUFFIX_OPTION, USE_COMPRESS_PROGRAM_OPTION,
VOLNO_FILE_OPTION, OBSOLETE_ABSOLUTE_NAMES, OBSOLETE_BLOCK_COMPRESS,
OBSOLETE_BLOCKING_FACTOR, OBSOLETE_BLOCK_NUMBER,
OBSOLETE_READ_FULL_RECORDS, OBSOLETE_TOUCH, OBSOLETE_VERSION_CONTROL):
Make sure they can't be valid chars, so they don't overlap with char codes.
Use an enum instead of a lot of #defines.
(long_options, main, usage): Remove --ending-file option.
(OPTION_STRING): Remove -E.