12306 XPG4v2 slave pty behaviour should generally be disabled
Reviewed by: Robert Mustacchi <rm@fingolfin.org>
Change-ID: I7ccd399c22866f34dd20c6bb9d28e77ba4e24c67

*** 20,30 ****
   */
  /*
   * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   * Copyright (c) 2018, Joyent, Inc.
!  * Copyright 2018 OmniOS Community Edition (OmniOSce) Association.
   */
  
  /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T      */
  /* All Rights Reserved                                  */
  
--- 20,30 ----
   */
  /*
   * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   * Copyright (c) 2018, Joyent, Inc.
!  * Copyright 2020 OmniOS Community Edition (OmniOSce) Association.
   */
  
  /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T      */
  /* All Rights Reserved                                  */
  
*** 4085,4095 ****
          if (sndsig == 0)
                  (void) putnextctl1(q, mtype, sig);
  
          if (c != '\0') {
                  if ((tp->t_echomp = allocb(4, BPRI_HI)) != NULL) {
!                         if (ldterm_echo(c, WR(q), 4, tp) > 0)
                                  putnext(WR(q), tp->t_echomp);
                          else
                                  freemsg(tp->t_echomp);
                          tp->t_echomp = NULL;
                  }
--- 4085,4096 ----
          if (sndsig == 0)
                  (void) putnextctl1(q, mtype, sig);
  
          if (c != '\0') {
                  if ((tp->t_echomp = allocb(4, BPRI_HI)) != NULL) {
!                         if (ldterm_echo(c, WR(q), 4, tp) > 0 ||
!                             (tp->t_state & TS_ISPTSTTY))
                                  putnext(WR(q), tp->t_echomp);
                          else
                                  freemsg(tp->t_echomp);
                          tp->t_echomp = NULL;
                  }