module Gem::VersionOption

def add_platform_option(task = command, *wrap)
  OptionParser.accept Gem::Platform do |value|
    if value == Gem::Platform::RUBY then
      value
    else
      Gem::Platform.new value
    end
  end
  add_option('--platform PLATFORM', Gem::Platform,
             "Specify the platform of gem to #{task}", *wrap) do
               |value, options|
    unless options[:added_platform] then
      Gem.platforms = [Gem::Platform::RUBY]
      options[:added_platform] = true
    end
    Gem.platforms << value unless Gem.platforms.include? value
  end
end