[NaCl SDK] nacl_io: Enable isatty running under sel_ldr.

native_client_sdk/src/libraries/nacl_io/devfs/tty_node.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef LIBRARIES_NACL_IO_DEVFS_TTY_NODE_H_
 #define LIBRARIES_NACL_IO_DEVFS_TTY_NODE_H_
 
 #include <poll.h>
 #include <pthread.h>
 
@@ skipping 20 matching lines @@
 
   virtual Error Write(const HandleAttr& attr,
                       const void* buf,
                       size_t count,
                       int* out_bytes);
 
   virtual Error Tcgetattr(struct termios* termios_p);
   virtual Error Tcsetattr(int optional_actions,
                           const struct termios* termios_p);
 
+  virtual Error Isatty() { return 0; }
+
  private:
   ScopedEventEmitter emitter_;
 
   Error ProcessInput(struct tioc_nacl_input_string* message);
   Error Echo(const char* string, int count);
   void InitTermios();
 
   std::deque<char> input_buffer_;
   struct termios termios_;
 
   /// Current height of terminal in rows.  Set via ioctl(2).
   int rows_;
   /// Current width of terminal in columns.  Set via ioctl(2).
   int cols_;
 
   // Output handler for TTY.  This is set via ioctl(2).
   struct tioc_nacl_output output_handler_;
   // Lock to protect output_handler_.  This lock gets aquired whenever
   // output_handler_ is used or set.
   sdk_util::SimpleLock output_lock_;
 };
 
 }  // namespace nacl_io
 
 #endif  // LIBRARIES_NACL_IO_DEVFS_TTY_NODE_H_