(read_and, list_archive, read_header, decode_mode, print_header,

(read_and, list_archive, read_header, decode_mode, print_header,
print_for_mkdir): Use mode_t, off_t, size_t when appropriate.  Remove
now-useless casts.  Use unsigned long to print *_t types, except use
STRINGIFY_BIGINT for off_t.

(read_header): Check for overflow when converting header size.

(from_oct): Now static.  Now returns uintmax_t.  `where' arg is now
const char *.  Size arg is now size_t.  Now takes new type and maxval
args.  Compute result using uintmax_t, not long.  Report error if
field does not contain octal number in range.
(gid_from_oct, major_from_oct, minor_from_oct, mode_from_oct,
off_from_oct, size_from_oct, time_from_oct, uid_from_oct,
uintmax_from_oct): New functions.

(stringify_uintmax_t_backwards): New function.

(decode_mode, print_for_mkdir): Mode arg is now mode_t.
(skip_file): Offset arg is now off_t.