Print something on stderr in case of exceptions in callback routines.
diff --git a/Mac/Modules/drag/Dragmodule.c b/Mac/Modules/drag/Dragmodule.c
index b029067..0775286 100644
--- a/Mac/Modules/drag/Dragmodule.c
+++ b/Mac/Modules/drag/Dragmodule.c
@@ -970,8 +970,10 @@
 		return -1;
 	rv = PyEval_CallObject((PyObject *)handlerRefCon, args);
 	Py_DECREF(args);
-	if ( rv == NULL )
+	if ( rv == NULL ) {
+		fprintf(stderr, "Drag: Exception in TrackingHandler\n");
 		return -1;
+	}
 	i = -1;
 	if ( rv == Py_None )
 		i = 0;
@@ -993,8 +995,10 @@
 		return -1;
 	rv = PyEval_CallObject((PyObject *)handlerRefCon, args);
 	Py_DECREF(args);
-	if ( rv == NULL )
+	if ( rv == NULL ) {
+		fprintf(stderr, "Drag: Exception in ReceiveHandler\n");
 		return -1;
+	}
 	i = -1;
 	if ( rv == Py_None )
 		i = 0;
@@ -1019,8 +1023,10 @@
 		return -1;
 	rv = PyEval_CallObject(self->sendproc, args);
 	Py_DECREF(args);
-	if ( rv == NULL )
+	if ( rv == NULL ) {
+		fprintf(stderr, "Drag: Exception in SendDataHandler\n");
 		return -1;
+	}
 	i = -1;
 	if ( rv == Py_None )
 		i = 0;