This fixes a MSVC warning Gisle Vanem reports.
const u_char *bp, u_int length, u_int nh,
const u_char *bp2);
extern void rrcp_print(netdissect_options *,const u_char *, u_int);
const u_char *bp, u_int length, u_int nh,
const u_char *bp2);
extern void rrcp_print(netdissect_options *,const u_char *, u_int);
-extern void loopback_print(netdissect_options *, const u_char *, u_int);
+extern void loopback_print(netdissect_options *, const u_char *, const u_int);
extern void ether_print(netdissect_options *,
const u_char *, u_int, u_int,
extern void ether_print(netdissect_options *,
const u_char *, u_int, u_int,