anchor.diff:    buildInputs = [ glib freetype cairo ]; # recommended by upstream
     propagatedBuildInputs = []
       ++ optional withGraphite2 graphite2
  -    ++ optionals withIcu [ icu harfbuzz ]
  -    ;
  +    ++ optionals withIcu [ icu harfbuzz ];
  +
  +  checkInputs = [ python ];
  +  doInstallCheck = false; # fails, probably a bug
   
     # Slightly hacky; some pkgs expect them in a single directory.
     postInstall = optionalString withIcu ''
  
positive.code:     sha256 = "0my6m9aqv4a8fc2pjwqx9pfdfh3a9mqvas4si4psi1b1867zi8y8";
    };
  
    outputs = [ "out" "dev" ];
    outputBin = "dev";
  
  
negative.code: , icu, graphite2, harfbuzz # The icu variant uses and propagates the non-icu one.
  , withIcu ? false # recommended by upstream as default, but most don't needed and it's big
  , withGraphite2 ? true # it is small and major distros do include it
  , python
  }:
  
  let
  