# File lib/rubygems.rb, line 146
    def bindir(install_dir=Gem.dir)
      return File.join(@build_root, File.join(install_dir, 'bin')) unless install_dir == File.join(@build_root, Gem.default_dir)

      if defined? RUBY_FRAMEWORK_VERSION then # mac framework support
        bin_dir = File.join(File.dirname(Config::CONFIG["sitedir"]),
                  File.basename(Config::CONFIG["bindir"]))
      else # generic install
        bin_dir = Config::CONFIG['bindir']
      end
      bin_dir = File.join(@build_root, bin_dir)
    end