anchor.diff:      platforms = platforms.unix;
       license = licenses.asl20;
       maintainers = with maintainers; [ dasisdormax ];
  -    broken = !gccStdenv.is64bit;
  +    broken = !stdenv.is64bit;
     };
   }
  
positive.code: 
    # The suffix of the binary to link as 'astcenc'
    mainBinary = builtins.replaceStrings
      [ "AVX2" "SSE41"  "SSE2" "NEON" "NONE" ]
      [ "avx2" "sse4.1" "sse2" "neon" "none" ]
      ( builtins.head isas );
  };
  
  gccStdenv.mkDerivation rec {
    pname = "astc-encoder";
    version = "4.2.0";
  
  
negative.code: { lib
  , stdenv
  , fetchFromGitHub
  , cmake
  , simdExtensions ? null
  