anchor.diff:      baseruby = self.override {
         useRailsExpress = false;
         docSupport = false;
  +      rubygemsSupport = false;
       };
       self = lib.makeOverridable (
         { stdenv, buildPackages, lib
         , fetchurl, fetchFromSavannah, fetchFromGitHub
         , useRailsExpress ? true
  +      , rubygemsSupport ? true
         , zlib, zlibSupport ? true
         , openssl, opensslSupport ? true
         , gdbm, gdbmSupport ? true
  
positive.code:         installFlags = stdenv.lib.optionalString docSupport "install-doc";
          # Bundler tries to create this directory
          postInstall = ''
            # Update rubygems
            pushd rubygems
            chmod +w bundler/bundler.gemspec
            ${buildRuby} setup.rb --destdir $GEM_HOME
            popd
  
            # Remove unnecessary groff reference from runtime closure, since it's big
            sed -i '/NROFF/d' $out/lib/ruby/*/*/rbconfig.rb
  
  
negative.code:             patchLevel = ver.patchLevel;
            }).${ver.majMinTiny};
  
          postUnpack = opString rubygemsSupport ''
            cp -r ${rubygems} $sourceRoot/rubygems
          '';
  
  