Fix signature of Dart_SetIntegerReturnValue.

runtime/include/dart_api.h

 /*
  * Copyright (c) 2012, 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.
  */
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
@@ skipping 2037 matching lines @@
 DART_EXPORT void Dart_SetReturnValue(Dart_NativeArguments args,
                                      Dart_Handle retval);
 
 DART_EXPORT void Dart_SetWeakHandleReturnValue(Dart_NativeArguments args,
                                                Dart_WeakPersistentHandle rval);
 
 DART_EXPORT void Dart_SetBooleanReturnValue(Dart_NativeArguments args,
                                             bool retval);
 
 DART_EXPORT void Dart_SetIntegerReturnValue(Dart_NativeArguments args,
-                                            intptr_t retval);
+                                            int64_t retval);
 
 DART_EXPORT void Dart_SetDoubleReturnValue(Dart_NativeArguments args,
                                            double retval);
 
 /**
  * A native function.
  */
 typedef void (*Dart_NativeFunction)(Dart_NativeArguments arguments);
 
 /**
@@ skipping 217 matching lines @@
  *
  * \param object An object.
  * \param peer A value to store in the peer field.
  *
  * \return Returns an error if 'object' is a subtype of Null, num, or
  *   bool.
  */
 DART_EXPORT Dart_Handle Dart_SetPeer(Dart_Handle object, void* peer);
 
 #endif  /* INCLUDE_DART_API_H_ */  /* NOLINT */