anchor.diff:      };
       "head" = {
         fetchzipversion = 5;
  -      version = "2018-02-15";
  -      rev = "7219376de42a1cc378ec957c886b511139d3c201";
  -      sha256 = "12c6446fdbd817709a5e7c2b1e8d523b14d40856b2675ed2f9d1c868170c7630";
  +      version = "2018-02-21";
  +      rev = "2aa737a99f5148f11031e764fd1bc57bfd04fd8b";
  +      sha256 = "70d886803df1759e2480fffab33c2d23ca17a96ae16e322489d0e2e78f600657";
       };
     };
     source = sources."${channel}";
  
positive.code: 
      nativeBuildInputs = [
        cmake
        ninja
      ] ++ (
        if (channel == "head") then [
          nasm
        ] else [
          yasm  # Remove for > 2.6
        ]
      );
  
      buildInputs = optionals (elem targetSystem platforms.linux) [
        numactl
  
negative.code: , lib
  , nasm
  , ninja
  
  , numactl
  
  