negative timestamps are handled correctly.
Replace invocations of xstrtol and xstrtoul with xstrtoumax, for
uniformity (and so that we don't need to have the other fns).
(main): Remove call to init_total_written; no longer needed.
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.
(intconv): Remove; use xstrto* fns instead.
("xstrtol.h"): Include.
(check_decimal): Remove.
(long_options, usage, OPTION_STRING, decode_options):
Remove -y, --bzip2, --unbzip2.
(decode_options): Use xget_version instead of get_version.
Check for overflow with -b and -L and RECORD_SIZE_OPTION.
Replace invocations of check_decimal with xstrtoumax.
uintmax_t value into new arg. Check for arithmetic overflow.
(decode_options): Avoid overflow if record_size fits in size_t but not int.
Check for overflow on user or group ids.
