message: Add check for device debug and hypre using GPU.
diff: #include "forall.hpp"
  #include "occa.hpp"
  +#ifdef MFEM_USE_MPI
  +#include <HYPRE_config.h> // HYPRE_USING_GPU
  +#endif
  #ifdef MFEM_USE_CEED
  #include "../fem/ceed/interface/util.hpp"
  #endif
  @@ -575,7 +578,13 @@ void Device::Setup(const int device_id)
  CeedDeviceSetup(device_option);
  }
  }
  - if (Allows(Backend::DEBUG_DEVICE)) { ngpu = 1; }
  + if (Allows(Backend::DEBUG_DEVICE))
  + {
  +#ifdef HYPRE_USING_GPU
  + MFEM_ABORT("Device debug does not support Hypre built for GPU.");
  +#endif
  + ngpu = 1;
  + }
  }
  } // mfem
  