if (!tmp->subject_changed) return (0);
if (tmp->subject_changed) return (1);
static int need_display_subject (CONTEXT *ctx, HEADER *tree){  HEADER *tmp;  if (tree->subject_changed)    return (1);  for (tmp = tree->prev; tmp; tmp = tmp->prev)  {    if (tmp->virtual >= 0 || (tmp->collapsed && (!ctx->pattern || tmp->limited)))    {      if (!tmp->subject_changed)	return (0);      else	break;    }  }  for (tmp = tree->parent; tmp; tmp = tmp->parent)  {    if (tmp->virtual >= 0 || (tmp->collapsed && (!ctx->pattern || tmp->limited)))      return (0);    else if (tmp->subject_changed)      return (1);  }  return (0);}