- (djm) [channels.c misc.c misc.h sshd.c] add missing setsockopt() to
   set IPV6_V6ONLY for local forwarding with GatwayPorts=yes. Unify
   setting IPV6_V6ONLY behind a new function misc.c:sock_set_v6only()
   report and fix from jan.kratochvil AT redhat.com
diff --git a/sshd.c b/sshd.c
index 13a455d..04d8f9f 100644
--- a/sshd.c
+++ b/sshd.c
@@ -979,15 +979,9 @@
 		    &on, sizeof(on)) == -1)
 			error("setsockopt SO_REUSEADDR: %s", strerror(errno));
 
-#ifdef IPV6_V6ONLY
 		/* Only communicate in IPv6 over AF_INET6 sockets. */
-		if (ai->ai_family == AF_INET6) {
-			if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY,
-			    &on, sizeof(on)) == -1)
-				error("setsockopt IPV6_V6ONLY: %s",
-				    strerror(errno));
-		}
-#endif
+		if (ai->ai_family == AF_INET6)
+			sock_set_v6only(listen_sock);
 
 		debug("Bind to port %s on %s.", strport, ntop);