ADD_ACKNOWLEDGER (Ledger_line_engraver, ledgered);
ADD_ACKNOWLEDGER (Ledger_line_engraver, staff_symbol);
ADD_TRANSLATOR (Ledger_line_engraver,
ADD_ACKNOWLEDGER (Ledger_line_engraver, ledgered);
ADD_ACKNOWLEDGER (Ledger_line_engraver, staff_symbol);
ADD_TRANSLATOR (Ledger_line_engraver,