prefer-remote-fetch: fix fetchurl eval

  fetchrepoproject = args: super.fetchrepoproject ({ preferLocalBuild = false; } // args);

  fetchs3 = args: super.fetchs3 ({ preferLocalBuild = false; } // args);

  fetchsvn = args: super.fetchsvn ({ preferLocalBuild = false; } // args);

  fetchurl = args: super.fetchurl ({ preferLocalBuild = false; } // args);

  fetchurl =

    fpArgs:

    super.fetchurl (

      super.lib.extends (finalAttrs: args: { preferLocalBuild = args.preferLocalBuild or false; }) (

        super.lib.toFunction fpArgs

      )

    );

  mkNugetSource = args: super.mkNugetSource ({ preferLocalBuild = false; } // args);

}