message: minor fix to isnan
diff: @@ -270,7 +270,7 @@ double TMOPNewtonSolver::ComputeScalingFactor(const Vector &x,
  }
  #endif
  - if (energy_out > 1.2*energy_in || isnan(energy_out) != 0)
  + if (energy_out > 1.2*energy_in || std::isnan(energy_out) != 0)
  {
  if (print_level >= 0)
  { mfem::out << "Scale = " << scale << " Increasing energy.\n"; }
  @@ -431,7 +431,7 @@ double TMOPDescentNewtonSolver::ComputeScalingFactor(const Vector &x,
  }
  #endif
  - if (energy_out > energy_in || isnan(energy_out) != 0)
  + if (energy_out > energy_in || std::isnan(energy_out) != 0)
  {
  scale *= 0.5;
  }
  