libc {
  GLIBC_2.0 {
    # helper functions
    __libc_init_first; __libc_start_main;
  }
  GLIBC_2.1 {
    # New special glibc functions.
    gnu_get_libc_release; gnu_get_libc_version;
  }
  GLIBC_PRIVATE {
    errno;
  }
}