message: Fixed unused variable for the serial build.
diff: @@ -3259,13 +3259,13 @@ void OrthoSolver::Orthogonalize(const Vector &v, Vector &v_ortho) const
  {
  double global_sum = v.Sum();
  int global_size = v.Size();
  -#ifdef MFEM_USE_MPI
  if (parallel)
  {
  +#ifdef MFEM_USE_MPI
  MPI_Allreduce(MPI_IN_PLACE, &global_sum, 1, MPI_DOUBLE, MPI_SUM, mycomm);
  MPI_Allreduce(MPI_IN_PLACE, &global_size, 1, MPI_INT, MPI_SUM, mycomm);
  - }
  #endif
  + }
  double ratio = global_sum / static_cast<double>(global_size);
  v_ortho.SetSize(v.Size());
  