Railguns can damage an actor multiple times with co_blockmapfix enabled
If an actor is overlapping more than one blockmap, the actor can receive damage from a single rail more than once with co_blockmapfix enabled. A fix was committed for similar behavior regarding rocket splash damage, however, railguns were ommitted. Perhaps a more robust blockthings iterator function is needed to handle this kind of problem automatically.
I've attached a patch to provide a two iterators for BlockThings. One iterates the blocks in column major form and the other in row major form. Both are needed due to vanilla Doom compatibility.
Just refreshing with a comment. "Needs me to put some eyes on it again" ~Sean