add module definition

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@908 bbd45198-f89e-11dd-88c7-29a3b14d5316

include/rtthread.h

@@ -293,6 +293,22 @@ rt_err_t  rt_device_control(rt_device_t dev, rt_uint8_t cmd, void* arg);
 /*@}*/
 #endif
 
+#ifdef RT_USING_MODULE
+/**
+ * @addtogroup Module
+ */
+/*@{*/
+/*
+ * module interface
+ */
+
+rt_module_t rt_module_load(const rt_uint8_t* name, void* module_ptr);
+rt_err_t rt_module_unload(rt_module_t module);
+rt_module_t rt_module_find(char* name);
+rt_module_t rt_module_self (void);
+
+#endif
+ 
 /*
  * interrupt service
  */