*: Port Christians tweaks for 32-bit route tags

Port over Christian's tweaks from his port of my commit widening the
route-tag field width to 32-bit.  Commit dc9ffce8786844
 "*: Consistently support 32-bit route tags".

with "changes which make this actually useful for all the daemons".

This is missing the zebra route-map changes.
diff --git a/ripngd/ripng_route.h b/ripngd/ripng_route.h
index fe65c88..9ff90aa 100644
--- a/ripngd/ripng_route.h
+++ b/ripngd/ripng_route.h
@@ -35,13 +35,13 @@
   u_char metric;		
 
   /* Tag field of RIPng packet.*/
-  u_short tag;		
+  u_int16_t tag;
 
   /* Route-map futures - this variables can be changed. */
   struct in6_addr nexthop_out;
   u_char metric_set;
   u_char metric_out;
-  u_short tag_out;
+  u_int16_t tag_out;
 };
 
 extern void ripng_aggregate_increment (struct route_node *rp,