GIZMO has lost its ghost

Running the SodShock with GIZMO configured crashes at the line:

843    counts[s->unlock_ind[k]] += 1;

in scheduler_set_unlocks, as this indexes counts out of bounds. The problem causing this is that we no longer have a ghost task so the unlock registration is bad in engine_make_hydro_loops_dependencies (i.e. c->super->ghost is NULL).

So one of the GIZMO experts needs to fix this so that it uses the newer ghost_in/out tasks or restores the standard ghost.