In case you are curious. You can use pond liner cut into strips to cover the crack of the doors. Attach it to one side (I use staples) make a small tent over the crack and attach the other side to the open door. Now when you close the door the pond liner will cover the crack and not interfere with the door opening or closing.

You can use door skin to make a 6"- 8" overlap strip to cover where 2 doors come together.