Add explicit includes for a few intrinsics.

src/shared/platform/win/nacl_exit.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
+#include <intrin.h>
 #include <stdlib.h>
 #include <stdio.h>
 
 #include "native_client/src/include/portability.h"
 #include "native_client/src/shared/platform/nacl_exit.h"
 #include "native_client/src/trusted/service_runtime/nacl_signal.h"
 
 
 /*
  * The MSVC compiler wrongly gives an "unreachable code" warning for
@@ skipping 55 matching lines @@
    *    ideal, but it is OK because NaClExit() should only be used for
    *    graceful exits (when no internal errors have been detected),
    *    and because there will be no other threads at this point.
    */
   ExitProcess(err_code);
 
   /* Just in case. */
   NaClAbort();
 #endif
 }