Create a build_config header file.

src/include/portability_string.h

 /*
  * Copyright 2008, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 20 matching lines @@
 
 
 /*
  * portability macros, etc. for string related stuff
  */
 
 #ifndef NATIVE_CLIENT_SRC_INCLUDE_PORTABILITY_STRING_H_
 #define NATIVE_CLIENT_SRC_INCLUDE_PORTABILITY_STRING_H_ 1
 
 #include <string.h>
+#include "native_client/src/include/build_config.h"
 
 typedef char utf8char_t;
 
 #if NACL_OSX
 /* NOTE:: Mac doesn't define strnlen in the headers. */
 #if defined( __cplusplus)
 extern "C"
 #endif
 size_t strnlen(const char* str, size_t max);
 #endif
 
 #if NACL_WINDOWS
 /* disable warnings for deprecated strncpy */
 #pragma warning(disable : 4996)
 
 #define STRDUP _strdup
 #define STRTOLL _strtoi64
 #define STRTOULL _strtoui64
 
 #else
 
 #define STRDUP strdup
 #define STRTOLL strtoll
 #define STRTOULL strtoull
 
 #endif
 
 #endif  /* NATIVE_CLIENT_SRC_INCLUDE_PORTABILITY_STRING_H_ */