anchor.diff:  
     BUILD_NAMEDTENSOR = true;
     BUILD_DOCS = buildDocs;
  +
  +  USE_MKL = blas.implementation == "mkl";
  +
  +  # Unlike MKL, MKLDNN is FOSS, so we enable support for it by default. Note
  +  # that this was renamed to dnnl and then renamed again to oneDNN upstream, but
  +  # pytorch still calls it by the old name mkldnn.
     USE_MKLDNN = mklDnnSupport;
  +  USE_MKLDNN_CBLAS = mklDnnSupport;
  +
     preBuild = ''
       export MAX_JOBS=$NIX_BUILD_CORES
       ${python.interpreter} setup.py build --cmake-only
  
positive.code:     done
    '';
  
  
    # Override the (weirdly) wrong version set by default. See
    # https://github.com/NixOS/nixpkgs/pull/52437#issuecomment-449718038
    # https://github.com/pytorch/pytorch/blob/v1.0.0/setup.py#L267
  
negative.code: 
    checkInputs = [ hypothesis ninja psutil ];
  
    # Tests take a long time and may be flaky, so just sanity-check imports
    doCheck = false;
    pythonImportsCheck = [
      "torch"
    ];
  
    checkPhase = with lib.versions; with lib.strings; concatStringsSep " " [
      cudaStubEnv
      "${python.interpreter} test/run_test.py"
      "--exclude"
  