*: 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/ripngd.h b/ripngd/ripngd.h
index 93f6ff1..ef6d56a 100644
--- a/ripngd/ripngd.h
+++ b/ripngd/ripngd.h
@@ -146,7 +146,7 @@
 struct rte
 {
   struct in6_addr addr;	/* RIPng destination prefix */
-  u_short tag;		/* RIPng tag */
+  u_int16_t tag;		/* RIPng tag */
   u_char prefixlen;	/* Length of the RIPng prefix */
   u_char metric;	/* Metric of the RIPng route */
   			/* The nexthop is stored by the structure
@@ -200,7 +200,7 @@
   struct in6_addr nexthop_out;
   u_char metric_set;
   u_char metric_out;
-  u_short tag_out;
+  u_int16_t tag_out;
 
   struct route_node *rp;
 };