Whisper.cpp intel iGPU working container 2 nix transition

Hi there,
I am trying to convert the docker (compose) setup from GitHub - tannisroot/wyoming-whisper-cpp-intel-gpu-docker: Run an Intel GPU-accelerated Wyoming protocol speech-to-text service for your Home Asssistant in Docker.

The difficult part is building the image via pkgs.dockerTools.

oneapiImage = pkgs.dockerTools.pullImage {
    imageName = "intel/oneapi"; #tag 2025.0.1-0-devel-ubuntu24.04  intel-basekit intel-opencl-icd libze-intel-gpu1 libze1 libze-dev 
    imageDigest = "sha256:f2bbcdeeaa4ad948f9d0341797adae84254fd8f090d16e4fa0ae5d1a995333be";
    hash = "sha256-WLXR0f/76zMiRitJ+nnLf5nvZqutjKU4B3Ad386nLoQ=";
    finalImageName = "intel/oneapi";
    finalImageTag = "2025.0.1-0-devel-ubuntu24.04";
};

imageFile = (pkgs.dockerTools.buildImage {
        name = "whisper-whisper-cpp";
        tag = "latest";
        fromImage = oneapiImage;
        diskSize = 20 * 1024;
        buildVMMemorySize = 20 * 1024;        
        #runAsRoot = ''
        # git clone https://github.com/ggerganov/whisper.cpp.git whisper.cpp \
        #  && cd whisper.cpp \
        #  && git reset --hard v${WHISPER_CPP_VERSION} \
        #  && cmake -B build -DGGML_SYCL=ON -DCMAKE_C_COMPILER=icx -DCMAKE_CXX_COMPILER=icpx -DGGML_SYCL_F16=ON \
        #  && cmake --build build -j --config Release
        #'';
        copyToRoot = pkgs.buildEnv {
          name = "image-root";
          pathsToLink = [ "/bin" ];
          paths = [ pkgs.whisper-cpp ];
        };
      });

if I use runAsRoot It works now but is a huge image.
So I decided to go even more the Nix way and tried to copyToRoot the pkgs.whisper-cpp.
I guess I need an overlay to get the build options in:

cmake -B build -DGGML_SYCL=ON -DCMAKE_C_COMPILER=icx -DCMAKE_CXX_COMPILER=icpx -DGGML_SYCL_F16=ON `

but the build is using the intel/oneapi toolchain of the container.
I think it uses these packages: intel-basekit intel-opencl-icd libze-intel-gpu1 libze1 libze-dev.
How to get these into Nix? Some of them are already, right?

Any ideas about the oneApi packages would be greatly appreciated!

You mean nixpkgs, and the way is via creating PRs.
Related: [Tracking] OneAPI Packages · Issue #367722 · NixOS/nixpkgs · GitHub