required_location

# File lib/rubygems.rb, line 879
  def self.required_location(gemname, libfile, *requirements)
    requirements = Gem::Requirement.default if requirements.empty?

    matches = Gem::Specification.find_all_by_name gemname, *requirements

    return nil if matches.empty?

    spec = matches.last
    spec.require_paths.each do |path|
      result = Gem::Path.path(spec.full_gem_path).add(path, libfile)
      return result if result.exist?
    end

    nil
  end