BUF_CHG
if (AT_BEGINNING(f) && Opt(c, O_BLANK) && ! Status(f, BUF_CHG) &&
Set(f, BUF_CHG);
Set(f, BUF_CHG);
Clr(p, WIN_CHG | BUF_CHG);
if (Status(f, BUF_CHG) || !Opt(c, O_PASSOK)) {
Clr(f, BUF_CHG);
Clr(f, WIN_CHG | BUF_CHG);