Add exitCode setter to set the exit code returned by the Dart VM

runtime/bin/io_natives.cc

 // 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.
 
 #include "bin/io_natives.h"
 
 #include <stdlib.h>
 #include <string.h>
 
 #include "bin/builtin.h"
@@ skipping 10 matching lines @@
   V(Crypto_GetRandomBytes, 1)                                                  \
   V(EventHandler_Start, 1)                                                     \
   V(EventHandler_SendData, 4)                                                  \
   V(Platform_NumberOfProcessors, 0)                                            \
   V(Platform_OperatingSystem, 0)                                               \
   V(Platform_PathSeparator, 0)                                                 \
   V(Platform_LocalHostname, 0)                                                 \
   V(Platform_Environment, 0)                                                   \
   V(Process_Start, 10)                                                         \
   V(Process_Kill, 3)                                                           \
+  V(Process_SetExitCode, 1)                                                    \
+  V(Process_Exit, 1)                                                           \
   V(ServerSocket_CreateBindListen, 4)                                          \
   V(ServerSocket_Accept, 2)                                                    \
   V(Socket_CreateConnect, 3)                                                   \
   V(Socket_Available, 1)                                                       \
   V(Socket_Read, 2)                                                            \
   V(Socket_ReadList, 4)                                                        \
   V(Socket_WriteList, 4)                                                       \
   V(Socket_GetPort, 1)                                                         \
   V(Socket_GetRemotePeer, 1)                                                   \
   V(Socket_GetError, 1)                                                        \
@@ skipping 32 matching lines @@
   int num_entries = sizeof(IOEntries) / sizeof(struct NativeEntries);
   for (int i = 0; i < num_entries; i++) {
     struct NativeEntries* entry = &(IOEntries[i]);
     if (!strcmp(function_name, entry->name_) &&
         (entry->argument_count_ == argument_count)) {
       return reinterpret_cast<Dart_NativeFunction>(entry->function_);
     }
   }
   return NULL;
 }