Don't log state changes if nothing user-visible has changed.

TODO

@@ -1,7 +1,5 @@
 Core
 ~~~~
-- kernel: persistent mode
-
 - client: Ctrl-R eats one more enter
 - client: paging?
 - client: data losses on large dumps?
@@ -12,8 +10,6 @@ Core
 - bgp: timing of updates?
 - bgp: dump and get_route_info
 
-- proto: Don't show repeated `Changed state to ...' messages if only internal states change
-
 Documentation
 ~~~~~~~~~~~~~
 - write doctool

nest/proto.c

@@ -59,7 +59,17 @@ proto_relink(struct proto *p)
 {
   list *l;
 
+  if (p->debug & D_STATES)
+    {
+      char *name = proto_state_name(p);
+      if (name != p->last_state_name_announced)
+	{
+	  p->last_state_name_announced = name;
 	  PD(p, "State changed to %s", proto_state_name(p));
+	}
+    }
+  else
+    p->last_state_name_announced = NULL;
   rem_node(&p->n);
   switch (p->core_state)
     {

nest/protocol.h

@@ -107,6 +107,7 @@ struct proto {
   unsigned reconfiguring;		/* We're shutting down due to reconfiguration */
   u32 hash_key;				/* Random key used for hashing of neighbors */
   bird_clock_t last_state_change;	/* Time of last state transition */
+  char *last_state_name_announced;	/* Last state name we've announced to the user */
 
   /*
    *	General protocol hooks: