Index: gcc-6-6.2.1-4.1/src/libgo/go/net/sockopt_gnu.go
===================================================================
--- /dev/null
+++ gcc-6-6.2.1-4.1/src/libgo/go/net/sockopt_gnu.go
@@ -0,0 +1,45 @@
+// 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 setDefaultSockopts(s, family, sotype int, ipv6only bool) error {
+	if family == syscall.AF_INET6 && sotype != syscall.SOCK_RAW {
+		// Allow both IP versions even if the OS default
+		// is otherwise.  Note that some operating systems
+		// never admit this option.
+		syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, boolint(ipv6only))
+	}
+	// Allow broadcast.
+	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1))
+}
+
+func setDefaultListenerSockopts(s int) error {
+	// Allow reuse of recently-used addresses.
+	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1))
+}
+
+func setDefaultMulticastSockopts(s int) error {
+	// Allow multicast UDP and raw IP datagram sockets to listen
+	// concurrently across multiple listeners.
+	if err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
+		return os.NewSyscallError("setsockopt", err)
+	}
+	// Allow reuse of recently-used ports.
+	// This option is supported only in descendants of 4.4BSD,
+	// to make an effective multicast application that requires
+	// quick draw possible.
+	// Not supported on GNU/Hurd
+	//if syscall.SO_REUSEPORT != 0 {
+	//	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1))
+	//}
+	return nil
+}