Create a build_config header file.

src/trusted/service_runtime/arch/x86_32/sel_addrspace_x86_32.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_LINUX
 #include <errno.h>
 #include <sys/mman.h>
 #endif
 
 #include "native_client/src/include/nacl_platform.h"
 #include "native_client/src/shared/platform/nacl_check.h"
 #include "native_client/src/trusted/service_runtime/include/sys/errno.h"
 #include "native_client/src/trusted/service_runtime/sel_addrspace.h"
 #include "native_client/src/trusted/service_runtime/sel_memory.h"
@@ skipping 50 matching lines @@
         " failed\n",
         (uintptr_t) *mem);
     return LOAD_NO_MEMORY_FOR_ADDRESS_SPACE;
   }
   NaClLog(4, "NaClAllocateSpace: %"NACL_PRIxPTR", %"NACL_PRIxS"\n",
           (uintptr_t) *mem,
           addrsp_size);
 
   return LOAD_OK;
 }