# File lib/sass/util.rb, line 1274
    def load_listen!
      if defined?(gem)
        begin
          gem 'listen', '>= 1.1.0', '< 3.0.0'
          require 'listen'
        rescue Gem::LoadError
          dir = scope("vendor/listen/lib")
          $LOAD_PATH.unshift dir
          begin
            require 'listen'
          rescue LoadError => e
            if version_geq(RUBY_VERSION, "1.9.3")
              version_constraint = "~> 3.0"
            else
              version_constraint = "~> 1.1"
            end
            e.message << "\n" <<
              "Run \"gem install listen --version '#{version_constraint}'\" to get it."
            raise e
          end
        end
      else
        begin
          require 'listen'
        rescue LoadError => e
          dir = scope("vendor/listen/lib")
          if $LOAD_PATH.include?(dir)
            raise e unless File.exist?(scope(".git"))
            e.message << "\n" <<
              'Run "git submodule update --init" to get the bundled version.'
          else
            $LOAD_PATH.unshift dir
            retry
          end
        end
      end
    end