log/syslog: disable on Windows

We want to be able to implement good Windows support
after Go 1.  Right now Windows tries to use Unix domain
sockets, and I'd rather just have it not be available.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5671076

src/pkg/log/syslog/syslog.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !windows,!plan9
+
 // Package syslog provides a simple interface to the system log service. It
 // can send messages to the syslog daemon using UNIX domain sockets, UDP, or
 // TCP connections.

src/pkg/log/syslog/syslog_test.go

 // Copyright 2009 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 !windows,!plan9
+
 package syslog
 
 import (

src/pkg/log/syslog/syslog_unix.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build !windows,!plan9
+
 package syslog
 
 import (