Add dummy threadExitMain routine.

src/libCom/osi/os/RTEMS/osdThread.c

@@ -152,6 +152,13 @@ threadWrapper (rtems_task_argument arg)
     rtems_task_delete (RTEMS_SELF);
 }
 
+/*
+ * The task wrapper takes care of cleanup
+ */
+void threadExitMain (void)
+{
+}
+
 /*
  * Report initialization failures
  */