[eyJhb]

Adds a defaultHow option, which is nice if you like me only want to deal with symlinks.
Unsure if this is wanted upstream, or if this is a patch I should just maintain myself.

[ElvishJerricco]

Hm, I dunno. I tend not to be a fan of things like this. It makes it so you can't just look at a definition and know what it did to the config, since this global default affects the defaults of the definition. Obviously the module system means you always have this problem no matter what, since any other module can always muck with any other definition; but I do prefer to minimize that kind of thing.