(TRUE, FALSE): Remove; all uses changed to true, false.

(TRUE, FALSE): Remove; all uses changed to true, false.
(enum number_format): Remove.
(FORMAT_RIGHT_NOLZ, FORMAT_RIGHT_LZ, FORMAT_LEFT): Now strings,
not enum values.
(DEFAULT_SECTION_DELIMITERS): Now an array constant, not a macro.
(section_del): Now const.
(print_fmt): Remove.
(starting_line_number, page_incr, blank_join, line_no,
print_lineno, proc_text, main):
Use intmax_t for line numbers.
(reset_numbers, have_read_stdin, build_type_arg, nl_file, main):
Use bool for booleans.
(lineno_format): Now a string, not an enum value.
(build_print_fmt): Remove.  All calls removed.  This work is
now doen within print_lineno.
(build_type_arg): Use size_t for sizes.
(print_lineno): Check for line number overflow.
(proc_text, main): Remove unnecessary cast.