Create a build_config header file.

src/trusted/service_runtime/sel_main_common.c

 /*
  * Copyright (c) 2014 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/trusted/service_runtime/sel_main_common.h"
+#include "native_client/src/include/nacl_defines.h"
 
 #if NACL_OSX
 #include <crt_externs.h>
 #endif
 
 #include "native_client/src/shared/platform/nacl_check.h"
 #include "native_client/src/trusted/service_runtime/sel_ldr.h"
 
 NaClErrorCode NaClMainLoadIrt(struct NaClApp *nap, struct NaClDesc *nd,
                               struct NaClValidationMetadata *metadata) {
@@ skipping 14 matching lines @@
   /* Mac dynamic libraries cannot access the environ variable directly. */
   envp = (const char **) *_NSGetEnviron();
 #else
   /* Overzealous code style check is overzealous. */
   /* @IGNORE_LINES_FOR_CODE_HYGIENE[1] */
   extern char **environ;
   envp = (const char **) environ;
 #endif
   return envp;
 }