Simplify cli_main

ports/nacl-spawn/include/nacl_main.h

 /*
  * 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.
  */
 
 #ifndef NACL_SPAWN_NACL_MAIN_H_
 #define NACL_SPAWN_NACL_MAIN_H_
 
 #include <spawn.h>
 
 #include "nacl_io/log.h"
 
 #if defined(NDEBUG)
 #define NACL_LOG(format, ...)
 #else
 #define NACL_LOG(format, ...) nacl_io_log(format, ##__VA_ARGS__)
 #endif
 
 __BEGIN_DECLS
 
 /*
  * Entry point expected by libcli_main.a
  */
-extern int nacl_main(int argc, char* argv[]);
+extern int nacl_main(int argc, char* argv[])
+    __attribute__ ((visibility ("default")));
 
 /*
  * Untar a startup bundle to a particular root.
  *
  * NOTE: This lives in libcli_main.a
  * Args:
  *   arg0: The contents of argv[0], used to determine relative tar location.
  *   tarfile: The name of a tarfile to extract.
  *   root: The absolute path to extract the startup tar file to.
  */
 extern int nacl_startup_untar(
     const char* argv0, const char* tarfile, const char* root);
 
 __END_DECLS
 
 #endif /* NACL_SPAWN_NACL_MAIN_H_ */