Hey there, I have a question about cross-compilation with flakebox. It seems to work perfectly as long as you don't have any external pkgs dependencies.

If you do, you want to be using pkgsCross.<target> instead of pkgs for the buildInputs and nativeBuildInputs, but there are no easy way to specify that with flakebox's craneMultiBuild.

A hacky way to manually make it work for a target is to specify the target's pkgs in your flake with:

    pkgs = import nixpkgs {
      localSystem = "x86_64-linux";
      crossSystem.config = "aarch64-unknown-linux-gnu";
    };

To make the cross-compilation work, but of course this is now imposing the aarch64 pkgs on all targets, which is not the point.

Am I missing something or is that a limitation of flakebox?
I did take a look at flakebox's source to make it work, but it doesn't seem like a trivial change. My idea would be to accept a pkgsCross function for craneMultiBuild that would look like this:

          nativeBuildInputs = pkgsCross: [
            pkgsCross.openssl
            pkgsCross.sqlite
          ];

This would somehow be forwarded to mkStdTargets where the correct pkgs would be resolved and later passed to mkTarget.

Thoughts about it?