anchor.diff:    buildInputs = [
       libnih
       util-linux_lib
  +  ] ++ optionals (channel == "dev") [
  +    keyutils
  +    libscrypt
  +    libsodium
     ];
   
     preBuild = ''
  
positive.code:       sha256 = "496ae8691eb9c5a233bd99ed7984cbe129d702c322dc540143cd4012b24a4dad";
      };
      "dev" = {
        version = "2016-01-15";
        rev = "006a6a003d9529d50ecee205340b7a109bde4d76";
        sha256 = "f23a4209e196fa0483bd82804aec8e21b368492746d61b3235b46c44f8c654d0";
      };
    };
  
    inherit (sources.${channel})
      rev
  
negative.code: { stdenv
  , fetchFromGitHub
  
  , keyutils
  , libnih
  , libscrypt
  , libsodium
  , util-linux_lib
  
  , channel ? "stable"
  