anchor.diff:      nativeBuildInputs = [
         cmake
         ninja
  -      yasm
  -    ];
  +    ] ++ (
  +      if (channel == "head") then [
  +        nasm
  +      ] else [
  +        yasm  # Remove for > 2.6
  +      ]
  +    );
   
       buildInputs = optionals (elem targetSystem platforms.linux) [
         numactl
  
positive.code: , fetchFromBitbucket
  , fetchurl
  , lib
  , ninja
  , yasm
  
  
negative.code:     nativeBuildInputs = [
        cmake
        ninja
      ] ++ (
        if (channel == "head") then [
          nasm
        ] else [
          yasm  # Remove for > 2.6
        ]
      );
  
      buildInputs = optionals (elem targetSystem platforms.linux) [
        numactl
  