void ldisc_update(int echo, int edit)
void ldisc_update(void *frontend, int echo, int edit)
void ldisc_update(int echo, int edit){    /*     * This is a stub in pterm. If I ever produce a Unix     * command-line ssh/telnet/rlogin client (i.e. a port of plink)     * then it will require some termios manoeuvring analogous to     * that in the Windows plink.c, but here it's meaningless.     */}