Changed packet drivers from services to plain processes.

Now tcpip_output() is a function pointer that is supposed to be set via the macro tcpip_set_outputfunc(). Packet drivers do so on process startup.

Thus if there are several packet drivers in a Contiki system the one started last is the one actually used. This behaviour is especially useful for the 'IP forwarding' "meta" packet driver.

cpu/native/net/tapdev.c

@@ -31,7 +31,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>
  *
- * $Id: tapdev.c,v 1.1 2007/03/31 18:49:40 adamdunkels Exp $
+ * $Id: tapdev.c,v 1.2 2007/05/20 21:32:24 oliverschmidt Exp $
  */
 
 #include <fcntl.h>
@@ -178,3 +178,8 @@ tapdev_send(void)
   }
 }
 /*---------------------------------------------------------------------------*/
+void
+tapdev_exit(void)
+{
+}
+/*---------------------------------------------------------------------------*/