diff --git a/unum/vendor/golang.org/x/net/ipv6/sys_asmreq_stub.go b/unum/vendor/golang.org/x/net/ipv6/sys_asmreq_stub.go
new file mode 100644
index 0000000..eece961
--- /dev/null
+++ b/unum/vendor/golang.org/x/net/ipv6/sys_asmreq_stub.go
@@ -0,0 +1,17 @@
+// Copyright 2013 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 !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris,!windows
+
+package ipv6
+
+import (
+	"net"
+
+	"golang.org/x/net/internal/socket"
+)
+
+func (so *sockOpt) setIPMreq(c *socket.Conn, ifi *net.Interface, grp net.IP) error {
+	return errOpNoSupport
+}