*: Widen width of Zserv routing tag field.

* lib/zebra.h: Introduce a route_tag_t type for route tags generally,
  and make it 4 bytes wide - so it can directly hold things like an ASN, or
  the OSPF ASE-LSA tag.
* zebra/rib.h: Use route_tag_t instead of u_short.
* *: Update 'u_short (*)?(tag|tmp)' to use route_tag_t instead of u_short.
  Update stream_{get,put} to l instead of w.
* ospf_zebra.c: (ospf_zebra_add) test OSPF tag within range of ROUTE_TAG_MAX.
diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
index e57d1af..405528c 100644
--- a/zebra/zebra_rib.c
+++ b/zebra/zebra_rib.c
@@ -2314,8 +2314,8 @@
 
 int
 static_add_ipv4_safi (safi_t safi, struct prefix *p, struct in_addr *gate,
-		      const char *ifname, u_char flags, u_short tag, u_char distance,
-		      vrf_id_t vrf_id)
+		      const char *ifname, u_char flags, route_tag_t tag,
+		      u_char distance, vrf_id_t vrf_id)
 {
   u_char type = 0;
   struct route_node *rn;
@@ -2411,7 +2411,8 @@
 
 int
 static_delete_ipv4_safi (safi_t safi, struct prefix *p, struct in_addr *gate,
-			 const char *ifname, u_short tag, u_char distance, vrf_id_t vrf_id)
+			 const char *ifname, route_tag_t tag, u_char distance,
+			 vrf_id_t vrf_id)
 {
   u_char type = 0;
   struct route_node *rn;
@@ -2797,7 +2798,7 @@
 /* Add static route into static route configuration. */
 int
 static_add_ipv6 (struct prefix *p, u_char type, struct in6_addr *gate,
-		 const char *ifname, u_char flags, u_short tag,
+		 const char *ifname, u_char flags, route_tag_t tag,
 		 u_char distance, vrf_id_t vrf_id)
 {
   struct route_node *rn;
@@ -2895,7 +2896,8 @@
 /* Delete static route from static route configuration. */
 int
 static_delete_ipv6 (struct prefix *p, u_char type, struct in6_addr *gate,
-		    const char *ifname, u_short tag, u_char distance, vrf_id_t vrf_id)
+		    const char *ifname, route_tag_t tag, u_char distance,
+		    vrf_id_t vrf_id)
 {
   struct route_node *rn;
   struct static_route *si;