diff -ruN dosbox-0.73/src/gui/midi_coreaudio.h dosbox-0.73-patched/src/gui/midi_coreaudio.h
--- dosbox-0.73/src/gui/midi_coreaudio.h	2009-05-25 20:44:46.000000000 +0200
+++ dosbox-0.73-patched/src/gui/midi_coreaudio.h	2010-03-03 13:53:44.000000000 +0100
@@ -17,6 +17,7 @@
  */
 
 #include <AudioToolbox/AUGraph.h>
+#include <CoreServices/CoreServices.h>
 
 // A macro to simplify error handling a bit.
 #define RequireNoErr(error)                                         \