Issues with heroicon when building Phoenix app with Nix

I was hoping to build the default Phoenix app using nix, but running into issues with the heroicons dependency. My gut feeling is that I have to patch it in the Nix derivation but haven’t been able to figure it out.

I made a contrived example here: GitHub - multivac61/phx-new-nix

Absorbing the heroicon dependency into priv/ caused the typical mixFodDeps build to succeed: GitHub - multivac61/phx-new-nix at absorb-heroicons