A small change to MST_Extra to add functionality to its Charcoal Purifier furniture

Awhile ago I built this thing trying to see what it could do only to find it could do nothing so I left it alone.
This morning I decided that I might as well try to do something about it for giggles.
I now understand why it did in fact do nothing O.O
So I changed it to allow for (infinite) clean water production at the expense of changed terrain requirements as well as increasing building cost… with charcoal.
This is choasvolt’s mod and this is simply a small change I thought some might like even if it’s a little cheaty.