* prefix.[hc]: Pass argument to the inet6_ntoa by value making it more
	  inet_ntoa alike.
	* ripngd.[hc], ripng_interface.c, ripng_peer.c: inet6_ntoa() takes
	  argument now by value.
diff --git a/lib/prefix.h b/lib/prefix.h
index 7ef5347..506d644 100644
--- a/lib/prefix.h
+++ b/lib/prefix.h
@@ -173,7 +173,7 @@
 void masklen2ip6 (int, struct in6_addr *);
 
 void str2in6_addr (const char *, struct in6_addr *);
-const char *inet6_ntoa (struct in6_addr *);
+const char *inet6_ntoa (struct in6_addr);
 
 #endif /* HAVE_IPV6 */