I thought that I had posted this here but couldn't find it. My wife was concerned about the sliding door in the bathroom having no way to lock shut. With a very simple mod, I added a pin lock to the door and am able to lock it in the open or closed position. Here's what I did.....
Very simple, remove existing strap that is used to hold the door open, drill where strap screw was into door when closed and open, install lock. It's up high because of the screw, if the screw wasn't there I would have mounted this a little lower.