anchor.diff:      buildInputs = lib.optional stdenv.isDarwin Security;
     };
   
  +  servo-fontconfig-sys = attrs: {
  +    nativeBuildInputs = [ pkg-config ];
  +    buildInputs = [ freetype ];
  +  };
  +
  +  skia-bindings = attrs: {
  +    nativeBuildInputs = [ python2 ];
  +  };
  +
     thrussh-libsodium = attrs: {
       nativeBuildInputs = [ pkg-config ];
       buildInputs = [ libsodium ];
  
positive.code:   dbus = attrs: {
      nativeBuildInputs = [ pkg-config ];
      buildInputs = [ dbus ];
    };
  
    foundationdb-sys = attrs: {
  
negative.code:   rink = attrs: {
      buildInputs = [ gmp ];
      crateBin = [{ name = "rink"; path = "src/bin/rink.rs"; }];
    };
  
    sdl2-sys = attr: {
      nativeBuildInputs = [ curl ];
    };
  
    security-framework-sys = attr: {
  