# File lib/multiruby.rb, line 386
  def self.update_rubygems
    warn "  Determining latest version for rubygems"
    html = URI.parse(GEM_URL).read

    versions = html.scan(/href="rubygems-update-(\d+(?:\.\d+)+).gem/i).flatten
    latest = versions.sort_by { |s| s.scan(/\d+/).map { |s| s.to_i } }.last

    Multiruby.in_versions_dir do
      file = "rubygems-#{latest}.tgz"
      unless File.file? file then
        warn "    Fetching rubygems-#{latest}.tgz via HTTP."
        File.unlink(*Dir["rubygems*"])
        File.open file, 'w' do |f|
          f.write URI.parse(GEM_URL+"/"+file).read
        end
      end
    end

    Multiruby.in_build_dir do
      FileUtils.rm_rf Dir["rubygems*"]
    end

    Multiruby.in_install_dir do
      FileUtils.rm_rf Dir["*"]
    end
  end