cmd/go/internal/renameio: use ERROR_ACCESS_DENIED to check for errors

CL 172418 added code to check for "Access is denied" error.
But "Access is denied" error will be spelled differently on
non-English version of Windows.

Check if error is ERROR_ACCESS_DENIED instead.

Updates #31247

Change-Id: I7b1633013d563f7c06c1f12a9be75122106834f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/174123
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

src/cmd/go/internal/renameio/error.go

@@ -0,0 +1,12 @@
+// Copyright 2019 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
+
+package renameio
+
+// isAccessDeniedError always returns false on non-windows.
+func isAccessDeniedError(err error) bool {
+	return false
+}

src/cmd/go/internal/renameio/error_windows.go

@@ -0,0 +1,23 @@
+// Copyright 2019 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 renameio
+
+import (
+	"os"
+	"syscall"
+)
+
+// isAccessDeniedError returns true if err was caused by ERROR_ACCESS_DENIED.
+func isAccessDeniedError(err error) bool {
+	linkerr, ok := err.(*os.LinkError)
+	if !ok {
+		return false
+	}
+	errno, ok := linkerr.Err.(syscall.Errno)
+	if !ok {
+		return false
+	}
+	return errno == syscall.ERROR_ACCESS_DENIED
+}

src/cmd/go/internal/renameio/renameio.go

@@ -11,8 +11,6 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"runtime"
-	"strings"
 	"time"
 )
 
@@ -66,7 +64,7 @@ func WriteToFile(filename string, data io.Reader) (err error) {
 	var start time.Time
 	for {
 		err := os.Rename(f.Name(), filename)
-		if err == nil || runtime.GOOS != "windows" || !strings.HasSuffix(err.Error(), "Access is denied.") {
+		if err == nil || !isAccessDeniedError(err) {
 			return err
 		}