Fixed Adlib compilation problem

svn-id: r6014

backends/midi/adlib.cpp

@@ -77,6 +77,7 @@ private:
 	void allocate() { _allocated = true; }
 
 public:
+	MidiDriver *device();
 	byte getNumber() { return _channel; }
 	void release() { _allocated = false; }
 
@@ -579,6 +580,11 @@ void AdlibPart::init (MidiDriver_ADLIB *owner, byte channel) {
 
 }
 
+MidiDriver *AdlibPart::device()
+{
+	return _owner;
+}
+
 void AdlibPart::noteOff (byte note)
 {
 	_owner->part_key_off (this, note);