libtextstyle: Avoid crashing the terminal emulator when using ncurses.
Reported by Adriaan de Groot <adridg@freebsd.org> in
<https://lists.gnu.org/archive/html/bug-gettext/2021-12/msg00023.html>.
Long explanation: <https://euroquis.nl/freebsd/2021/11/24/bison.html>
* libtextstyle/gnulib-local/lib/term-ostream.oo.c (out_data_string,
out_data_string_unchecked): New functions.
(out_hyperlink_change): Don't use tputs on strings that are not escape
sequences.
