Quoting Sean Whitton <spwhit...@spwhitton.name>:
Typically we try to patch out the need for build-deps like this. Have you tried to do that?
Thanks for the suggestion, I'll do that! I did that for the current version of the package (which uses cask, not eask). And I can probably keep it that way. I wonder, if that is the right direction for the future, in case more and more packages use such build tools? But maybe this bug is not the right place to discuss it.