O_CBREAK
sb.sg_flags &= ~O_CBREAK;
sb.sg_flags |= O_CBREAK;
sb.sg_flags &= ~(O_CBREAK|O_RAW|O_TBDELAY);
sb.sg_flags |= (eight ? O_RAW : O_CBREAK);
#define CBREAK O_CBREAK
if (!(csp->t_flags & O_CBREAK))
csp->t_flags |= O_CBREAK;
#define CBREAK O_CBREAK