(convert_entire_line, have_read_stdin, parse_tabstops,

(convert_entire_line, have_read_stdin, parse_tabstops,
next_file, expand, main):
Use bool for booleans.
(tab_size, tab_list, add_tabstop, parse_tabstops, validate_tabstops,
expand, main):
Use uintmax_t for column counts.
(add_tabstop): Don't reserve -1 (now UINTMAX_MAX) as a special value.
All callers changed.
(parse_tabstops): Don't pass a negative char to isblank.
Avoid memory leak with large tab stops.
(validate_tabstops, expand): Don't assume number of tab stops is
<= INT_MAX.
(next_file, main): Use EXIT_SUCCESS/EXIT_FAILURE rather than 0/1 when
storing values into exit_status.
(expand): Use same pattern as unexpand for reading chars.
Report an error when input line is too long, instead of silently
screwing up.  Do not mishandle tab stops when backspacing left
over start of line.