How do we deal with packaging VST2 plugins?

I’ve created a draft PR for squeezer, a nice VST plugin for audio compression. The packaging is… clunky, because the project relies on external SDKs like juce, vst3 and vst2.

My concern is VST2, as I understand, it is proprietary and non-redistributable. How would we work around it so that we could have VSTs packaged in nixpkgs for audio people using Nix and NixOS?

Edit: in this specific case, fortunately there seems to be a plan to introduce vst3

You may be interested by the discussion here bespokesynth: possible license violation in the derivation · Issue #145607 · NixOS/nixpkgs · GitHub. For BespokeSynth for instance we provide two packages, one that does not provide any vst compatibility, and fulfill the license, and one that does include it but must be built by the user instead of hydra.