message: cannot give an argc to openmpi's MPI_Init() less than the one in main() [?]
  [ci skip]
diff: @@ -52,8 +52,8 @@ namespace ospray {
  initialized = true;
  - int _ac = 2;
  - const char *_av[] = {"ospray_mpi_worker", "--osp:mpi"};
  + int _ac = 1;
  + const char *_av[] = {"ospray_mpi_worker"};
  mpi::init(&_ac, _av);
  