# File setup.rb, line 878
  def dive_into(rel)
    return unless File.dir?("#{@srcdir}/#{rel}")

    dir = File.basename(rel)
    Dir.mkdir dir unless File.dir?(dir)
    prevdir = Dir.pwd
    Dir.chdir dir
    $stderr.puts '---> ' + rel if verbose?
    @currdir = rel
    yield
    Dir.chdir prevdir
    $stderr.puts '<--- ' + rel if verbose?
    @currdir = File.dirname(rel)
  end