message: Add copyright header
  Change name of header guard to remove double-underscore
diff: -#ifndef __LOR_MMS_HPP__
  -#define __LOR_MMS_HPP__
  +// Copyright (c) 2010-2021, Lawrence Livermore National Security, LLC. Produced
  +// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
  +// LICENSE and NOTICE for details. LLNL-CODE-806117.
  +//
  +// This file is part of the MFEM library. For more information and source code
  +// availability visit https://mfem.org.
  +//
  +// MFEM is free software; you can redistribute it and/or modify it under the
  +// terms of the BSD-3 license. We welcome feedback and contributions, see file
  +// CONTRIBUTING.md for details.
  +
  +#ifndef MFEM_LOR_MMS_HPP
  +#define MFEM_LOR_MMS_HPP
  extern bool grad_div_problem;
  