Update internal MUNT to version 2.7.0

src/sound/munt/Poly.h

@@ -1,5 +1,5 @@
 /* Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009 Dean Beeler, Jerome Fisher
- * Copyright (C) 2011-2020 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
+ * Copyright (C) 2011-2022 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU Lesser General Public License as published by
@@ -41,6 +41,8 @@ private:
 
 	Poly *next;
 
+	void setState(PolyState state);
+
 public:
 	Poly();
 	void setPart(Part *usePart);