Fixed another Mac compile error

macosx/coremidi/JackCoreMidiOutputPort.mm

@@ -28,6 +28,10 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 #include "JackTime.h"
 #include "JackError.h"
 
+/* Somehow the compiler doesn't accept my typedef in JackMidi.h */
+typedef jack_event_data_t            jack_midi_data_t;
+typedef jack_event_t                 jack_midi_event_t;
+
 using Jack::JackCoreMidiOutputPort;
 
 JackCoreMidiOutputPort::JackCoreMidiOutputPort(double time_ratio,