anchor.diff:  
       nativeBuildInputs = [
         cmake
  +      nasm
         ninja
  -    ] ++ (
  -      if (channel == "head") then [
  -        nasm
  -      ] else [
  -        yasm  # Remove for > 2.6
  -      ]
  -    );
  +    ];
   
       buildInputs = optionals (elem targetSystem platforms.linux) [
         numactl
  
positive.code:     };
      "head" = {
        fetchzipversion = 5;
        version = "2018-02-15";
        rev = "7219376de42a1cc378ec957c886b511139d3c201";
        sha256 = "12c6446fdbd817709a5e7c2b1e8d523b14d40856b2675ed2f9d1c868170c7630";
      };
    };
    source = sources."${channel}";
  
negative.code: , lib
  , nasm
  , ninja
  
  , numactl
  
  