libc {

  GLIBC_2.1 {

    # variables in normal name space

    argp_err_exit_status; argp_program_bug_address; argp_program_version;

    argp_program_version_hook;

    # a*

    argp_error; argp_failure; argp_help; argp_parse; argp_state_help;

    argp_usage;

  }

}