Class 'MIDISceneChange' now needs to be visible outside of libardour

libs/ardour/ardour/midi_scene_change.h

@@ -22,6 +22,7 @@
 
 #include "pbd/signals.h"
 
+#include "ardour/libardour_visibility.h"
 #include "ardour/scene_change.h"
 
 namespace ARDOUR
@@ -29,7 +30,7 @@ namespace ARDOUR
 
 class MidiPort;
 
-class MIDISceneChange : public SceneChange
+class LIBARDOUR_API MIDISceneChange : public SceneChange
 {
   public:
 	MIDISceneChange (int channel, int bank = -1, int program = -1);