build_extension

# File lib/rubygems/ext/builder.rb, line 146
  def build_extension extension, dest_path # :nodoc:
    results = []

    extension ||= '' # I wish I knew why this line existed
    extension_dir =
      File.expand_path File.join @gem_dir, File.dirname(extension)
    lib_dir = File.join @spec.full_gem_path, @spec.raw_require_paths.first

    builder = builder_for extension

    begin
      FileUtils.mkdir_p dest_path

      CHDIR_MUTEX.synchronize do
        Dir.chdir extension_dir do
          results = builder.build(extension, @gem_dir, dest_path,
                                  results, @build_args, lib_dir)

          say results.join("\n") if Gem.configuration.really_verbose
        end
      end

      write_gem_make_out results.join "\n"
    rescue => e
      results << e.message
      build_error extension_dir, results.join("\n"), $@
    end
  end