anchor.diff:      i686-linux = "linux-i686";
       x86_64-darwin = "darwin-x86_64";
       aarch64-darwin = "darwin-universal";
  +    aarch64-linux = "linux-aarch64";
     };
   
     arch = archs.${stdenv.system} or (throw "system ${stdenv.system} not supported");
     isAarch64Darwin = stdenv.system == "aarch64-darwin";
   
     checkInputs = [ git gmp openssl readline libxml2 libyaml ];
  +
  +  binaryUrl = version: rel:
  +    if arch == archs.aarch64-linux then
  +      "https://dev.alpinelinux.org/archive/crystal/crystal-${version}-aarch64-alpine-linux-musl.tar.gz"
  +    else
  +      "https://github.com/crystal-lang/crystal/releases/download/${version}/crystal-${version}-${toString rel}-${arch}.tar.gz";
   
     genericBinary = { version, sha256s, rel ? 1 }:
       stdenv.mkDerivation rec {
  
positive.code:       x86_64-linux = "1949argajiyqyq09824yj3wjyv88gd8wbf20xh895saqfykiq880";
        i686-linux = "0w0f4fwr2ijhx59i7ppicbh05hfmq7vffmgl7lal6im945m29vch";
        x86_64-darwin = "01n0rf8zh551vv8wq3h0ifnsai0fz9a77yq87xx81y9dscl9h099";
      };
    };
  
  
negative.code:       inherit version;
  
        src = fetchurl {
          url = binaryUrl version rel;
          sha256 = sha256s.${stdenv.system};
        };
  
  