anchor.diff:          doCheck ? true,
           requireX ? false,
           broken ? false,
  -        hydraPlatforms ? hydraPlatforms',
  +        platforms ? R.meta.platforms,
  +        hydraPlatforms ? if hydraPlatforms' != null then hydraPlatforms' else platforms,
           maintainers ? []
         }: buildRPackage {
       name = "${name}-${version}";
  
positive.code:     propagatedBuildInputs = depends;
      nativeBuildInputs = depends;
      meta.homepage = mkHomepage (args // { inherit name; });
      meta.platforms = R.meta.platforms;
      meta.hydraPlatforms = hydraPlatforms;
      meta.broken = broken;
      meta.maintainers = maintainers;
  
negative.code:   #
    # some packages, e.g. cncaGUI, require X running while installation,
    # so that we use xvfb-run if requireX is true.
    mkDerive = {mkHomepage, mkUrls, hydraPlatforms ? null}: args:
      let hydraPlatforms' = hydraPlatforms; in
        lib.makeOverridable ({
          name, version, sha256,
  