runtime: add missing copyright

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7884045

src/pkg/runtime/arch_386.h

+// 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.
+
 enum {
 	thechar = '8',
 	BigEndian = 0,

src/pkg/runtime/arch_amd64.h

+// 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.
+
 enum {
 	thechar = '6',
 	BigEndian = 0,

src/pkg/runtime/arch_arm.h

+// 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.
+
 enum {
 	thechar = '5',
 	BigEndian = 0,

src/pkg/runtime/os_freebsd.c

-// Use of this source file is governed by a BSD-style
-// license that can be found in the LICENSE file.`
+// 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.
 
 #include "runtime.h"
 #include "defs_GOOS_GOARCH.h"

src/pkg/runtime/os_freebsd.h

+// 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.
+
 #define SS_DISABLE 4
 
 int32	runtime·thr_new(ThrParam*, int32);

src/pkg/runtime/os_netbsd.c

-// Use of this source file is governed by a BSD-style
-// license that can be found in the LICENSE file.`
+// 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.
 
 #include "runtime.h"
 #include "defs_GOOS_GOARCH.h"

src/pkg/runtime/os_openbsd.c

-// Use of this source file is governed by a BSD-style
-// license that can be found in the LICENSE file.`
+// 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.
 
 #include "runtime.h"
 #include "defs_GOOS_GOARCH.h"

src/pkg/runtime/signals_plan9.h

+// 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.
+
 #define N SigNotify
 #define T SigThrow
 #define P SigPanic

src/pkg/runtime/string_test.go

+// Copyright 2012 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.
+
 package runtime_test
 
 import (