Index: gcc-6-6.2.1-4.1/src/libgo/go/net/sockoptip_gnu.go
===================================================================
--- /dev/null
+++ gcc-6-6.2.1-4.1/src/libgo/go/net/sockoptip_gnu.go
@@ -0,0 +1,30 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build gnu
+
+package net
+
+import (
+	"os"
+	"syscall"
+)
+
+func setIPv4MulticastInterface(fd *netFD, ifi *Interface) error {
+	ip, err := interfaceToIPv4Addr(ifi)
+	if err != nil {
+		return os.NewSyscallError("setsockopt", err)
+	}
+	var a [4]byte
+	copy(a[:], ip.To4())
+	if err := fd.incref(); err != nil {
+		return err
+	}
+	defer fd.decref()
+	return os.NewSyscallError("setsockopt", syscall.SetsockoptInet4Addr(fd.sysfd, syscall.IPPROTO_IP, syscall.IP_MULTICAST_IF, a))
+}
+
+func setIPv4MulticastLoopback(fd *netFD, v bool) error {
+	return syscall.ENOPROTOOPT
+}