sudo_term_raw: change the isig argument into a flags field

There are current two flags: SUDO_TERM_ISIG (enable terminal signals)
and SUDO_TERM_OFLAG (preserve output flags).

plugins/sudoers/sudoreplay.c

@@ -629,7 +629,7 @@ setup_terminal(struct eventlog *evlog, bool interactive, bool resize)
     /* Open fd for /dev/tty and set to raw mode. */
     if (interactive) {
 	ttyfd = open(_PATH_TTY, O_RDWR);
-	while (!sudo_term_raw(ttyfd, 1)) {
+	while (!sudo_term_raw(ttyfd, SUDO_TERM_ISIG)) {
 	    if (errno != EINTR)
 		sudo_fatal("%s", U_("unable to set tty to raw mode"));
 	    kill(getpid(), SIGTTOU);