Fix Stdio->Stdin typo and missing external.

runtime/bin/stdio_patch.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 patch class _StdIOUtils {
-  static Stdio _getStdioInputStream() {
+  static Stdin _getStdioInputStream() {
     switch (_getStdioHandleType(0)) {
       case _STDIO_HANDLE_TYPE_TERMINAL:
       case _STDIO_HANDLE_TYPE_PIPE:
       case _STDIO_HANDLE_TYPE_SOCKET:
         return new Stdin._(new _Socket._readPipe(0));
       case _STDIO_HANDLE_TYPE_FILE:
         return new Stdin._(new _FileStream.forStdin());
       default:
         throw new FileException("Unsupported stdin type");
     }
@@ skipping 23 matching lines @@
 }
 
 patch class Stdin {
   /* patch */ int readByteSync() native "Stdin_ReadByte";
 }
 
 
 _getStdioHandle(_NativeSocket socket, int num) native "Socket_GetStdioHandle";
 _getStdioHandleType(int num) native "File_GetStdioHandleType";
 _getSocketType(_NativeSocket nativeSocket) native "Socket_GetType";