There is nothing built-in for it per se. I think you just have to sign the application from a postbuild hook, I think. I remember discussing this with the person that contributed the Mac build, but I don't remember the result of the discussion exactly. I think that was it though.
That looks very interesting. Thanks for creating and sharing. This wasn't available back when I used Löve. Maybe I should give it another shot. I will certainly try your tool!