mutt_error _("Threading is not enabled."); return (-1);
return (1);
int mutt_messages_in_thread (HEADER *cur){  HEADER *top;  int n = 1;   if ((Sort & SORT_MASK) != SORT_THREADS)  {    mutt_error _("Threading is not enabled.");    return (-1);  }  /* find top parent */  while (cur->parent)    cur = cur->parent;  top = cur;   /* return if there are no children at all */  if ((cur = cur->child) == NULL)    return n;  FOREVER  {    n++;    if (cur->child)      cur = cur->child;    else if (cur->next)      cur = cur->next;    else     {      while (!cur->next)       {        cur = cur->parent;        if (cur == top)          return n;      }      cur = cur->next;    }  }  /* not reached */}