Create a build_config header file.

src/trusted/service_runtime/arch/x86_64/sel_rt_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 <float.h>
 #include <string.h>
 
+#include "native_client/src/include/build_config.h"
+
 /*
  * This header declares the _mm_getcsr function.
  */
 #if NACL_WINDOWS
 #include <mmintrin.h>
 #else
 #include <xmmintrin.h>
 #endif
 
 #include "native_client/src/shared/platform/nacl_log.h"
@@ skipping 107 matching lines @@
   sig_ctx->rsi       = 0;
   sig_ctx->rdi       = 0;
 
   sig_ctx->r8        = 0;
   sig_ctx->r9        = 0;
   sig_ctx->r10       = 0;
   sig_ctx->r11       = 0;
 
   sig_ctx->flags     = 0;
 }