Create a build_config header file.

src/trusted/service_runtime/arch/x86_64/nacl_tls_64.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 "native_client/src/include/build_config.h"
+
 #if NACL_OSX
 # include <pthread.h>
 #endif
 
 #include "native_client/src/include/portability.h"
 #include "native_client/src/include/nacl_macros.h"
 
 #include "native_client/src/shared/platform/nacl_check.h"
 #include "native_client/src/shared/platform/nacl_sync_checked.h"
 #include "native_client/src/trusted/service_runtime/arch/x86/sel_ldr_x86.h"
@@ skipping 266 matching lines @@
   nacl_current_thread = &natp->user;
 }
 
 struct NaClAppThread *NaClTlsGetCurrentThread(void) {
   return NaClAppThreadFromThreadContext(nacl_current_thread);
 }
 
 #else
 # error "Woe to the service runtime.  What OS is it being compiled for?!?"
 #endif