Revert "freebsd: ignore IPv6 for now"

This reverts commit 061422affc.

We have a way to support IPv6 on FreeBSD now.

Signed-off-by: Denton Gentry <dgentry@tailscale.com>

wgengine/router/dns/config.go

@@ -10,8 +10,6 @@ import (
 	"tailscale.com/types/logger"
 )
 
-//go:generate go run tailscale.com/cmd/cloner -type=Config -output=config_clone.go
-
 // Config is the set of parameters that uniquely determine
 // the state to which a manager should bring system DNS settings.
 type Config struct {

wgengine/router/dns/config_clone.go

@@ -1,33 +0,0 @@
-// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Code generated by tailscale.com/cmd/cloner -type Config; DO NOT EDIT.
-
-package dns
-
-import (
-	"inet.af/netaddr"
-)
-
-// Clone makes a deep copy of Config.
-// The result aliases no memory with the original.
-func (src *Config) Clone() *Config {
-	if src == nil {
-		return nil
-	}
-	dst := new(Config)
-	*dst = *src
-	dst.Nameservers = append(src.Nameservers[:0:0], src.Nameservers...)
-	dst.Domains = append(src.Domains[:0:0], src.Domains...)
-	return dst
-}
-
-// A compilation failure here means this code must be regenerated, with command:
-//   tailscale.com/cmd/cloner -type Config
-var _ConfigNeedsRegeneration = Config(struct {
-	Nameservers []netaddr.IP
-	Domains     []string
-	PerDomain   bool
-	Proxied     bool
-}{})