anchor.diff:      bazelFlags = [
         # temporary fixes to make the build work with bazel 0.27
         "--incompatible_no_support_tools_in_action_inputs=false"
  -    ] ++ lib.optional sse42Support "--copt=-msse4.2"
  -      ++ lib.optional avx2Support "--copt=-mavx2"
  -      ++ lib.optional fmaSupport "--copt=-mfma";
  +    ];
  +    bazelBuildFlags = [
  +      "--config=opt" # optimize using the flags set in the configure phase
  +    ];
   
       bazelTarget = "//tensorflow/tools/pip_package:build_pip_package //tensorflow/tools/lib_package:libtensorflow";
   
  
positive.code:       export PATH="$PWD/dummy-ldconfig:$PATH"
  
        export PYTHON_LIB_PATH="$NIX_BUILD_TOP/site-packages"
        mkdir -p "$PYTHON_LIB_PATH"
      '';
  
  
negative.code: 
        # cudaSupport causes fetch of ncclArchive, resulting in different hashes
        sha256 = if cudaSupport then
          "07p6f3rbdw7y2ky5wrldjcvzdzhcynlmmydwb7cz12iphazhmipy"
        else
          "1d67h0n461cyfimzlsj6bv9p95iv9jhglr0izdc6y0n6w09z8pw0";
      };
  