diff --git a/src/include/resolv.h b/src/include/resolv.h
index 1f9cf6a8..a4d3b108 100644
--- a/src/include/resolv.h
+++ b/src/include/resolv.h
@@ -1,4 +1,33 @@
-/*	$OpenBSD: resolv.h,v 1.3 1997/03/13 19:11:51 downsj Exp $	*/
+/*	$OpenBSD: resolv.h,v 1.4 2000/06/22 07:31:18 itojun Exp $	*/
+
+/*
+ * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
 
 /*
  * ++Copyright++ 1983, 1987, 1989, 1993
@@ -70,6 +99,7 @@
 # include <sys/types.h>
 #endif
 #include <sys/cdefs.h>
+#include <sys/socket.h>
 #include <stdio.h>
 
 /*
@@ -128,6 +158,23 @@ struct __res_state {
 	char	pad[68];		/* on an i386 this means 512b total */
 };
 
+#if 1 /* INET6 */
+/*
+ * replacement of __res_state, separated to keep binary compatibility.
+ */
+struct __res_state_ext {
+	struct sockaddr_storage nsaddr_list[MAXNS];
+	struct {
+		int	af;		/* address family for addr, mask */
+		union {
+			struct in_addr ina;
+			struct in6_addr in6a;
+		} addr, mask;
+	} sort_list[MAXRESOLVSORT];
+};
+#endif
+
+
 /*
  * Resolver options (keep these in synch with res_debug.c, please)
  */
@@ -193,6 +240,9 @@ struct res_sym {
 };
 
 extern struct __res_state _res;
+#if 1 /* INET6 */
+extern struct __res_state_ext _res_ext;
+#endif
 extern const struct res_sym __p_class_syms[];
 extern const struct res_sym __p_type_syms[];