8527 tty buffer/queue sizes should be larger

*** 378,388 ****
          sop = (struct stroptions *)mop->b_rptr;
          if (oflag & FNOCTTY)
                  sop->so_flags = SO_HIWAT | SO_LOWAT;
          else
                  sop->so_flags = SO_HIWAT | SO_LOWAT | SO_ISTTY;
!         sop->so_hiwat = 512;
          sop->so_lowat = 256;
          putnext(rqp, mop);
  
          /*
           * The input, devp, is a major device number, the output is put
--- 378,388 ----
          sop = (struct stroptions *)mop->b_rptr;
          if (oflag & FNOCTTY)
                  sop->so_flags = SO_HIWAT | SO_LOWAT;
          else
                  sop->so_flags = SO_HIWAT | SO_LOWAT | SO_ISTTY;
!         sop->so_hiwat = _TTY_BUFSIZ;
          sop->so_lowat = 256;
          putnext(rqp, mop);
  
          /*
           * The input, devp, is a major device number, the output is put