anchor.diff:  
         # cudaSupport causes fetch of ncclArchive, resulting in different hashes
         sha256 = if cudaSupport then
  -        "0gmwwcld8hm1nfxmx2w2gqxjxq5b5ln7vbxn0x63x9yy7avs3dkp"
  +        "07p6f3rbdw7y2ky5wrldjcvzdzhcynlmmydwb7cz12iphazhmipy"
         else
           "1d67h0n461cyfimzlsj6bv9p95iv9jhglr0izdc6y0n6w09z8pw0";
       };
  
positive.code:       export PATH="$PWD/dummy-ldconfig:$PATH"
  
        export PYTHON_LIB_PATH="$NIX_BUILD_TOP/site-packages"
        mkdir -p "$PYTHON_LIB_PATH"
      '';
  
  
negative.code:       sed -i '/tensorboard >=/d' tensorflow/tools/pip_package/setup.py
      '';
  
      preConfigure = let
        opt_flags = []
          ++ lib.optionals sse42Support ["-msse4.2"]
          ++ lib.optionals avx2Support ["-mavx2"]
          ++ lib.optionals fmaSupport ["-mfma"];
      in ''
        patchShebangs configure
  
        # dummy ldconfig
  