# File lib/backports/tools.rb, line 4
  def self.require_relative(relative_feature)
    file = caller.first.split(/:\d/,2).first
    if /\A\((.*)\)/ =~ file # eval, etc.
      raise LoadError, "require_relative is called in #{$1}"
    end
    require File.expand_path(relative_feature, File.dirname(file))
  end