Hi,

I independently ran into and fixed this issue myself, but seeing Ludo's
patch, I'll probably run with that.

@Ludo: I tested your patch on my setup (inside a VM); it needed a few small
fixups (an export was missing and the (apply ...) wasn't working for
some reason), but other than that it worked for me.  I was able to add a
#:key-file parameter to my LUKS device with your patch.  You just need
to apply my fixup on top of your patch.

Cheers,
Quentin