glibc/nptl/sysdeps/unix/sysv/linux/Versions

libc {
  GLIBC_PRIVATE {
    __register_atfork; __libc_pthread_init;
    __libc_current_sigrtmin_private; __libc_current_sigrtmax_private;
    __libc_allocate_rtsig_private;
  }
}
libpthread {
  GLIBC_2.0 {
    fork; __fork;
  }
}