# File src/ruby_supportlib/phusion_passenger/platform_info/binary_compatibility.rb, line 60
    def self.ruby_extension_binary_compatibility_id
      ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : "ruby"
      ruby_ext_version = RUBY_VERSION
      if RUBY_PLATFORM =~ /darwin/
        if RUBY_PLATFORM =~ /universal/
          ruby_arch = "universal"
        else
          # OS X <  10.8: something like:
          #   "/opt/ruby-enterprise/bin/ruby: Mach-O 64-bit executable x86_64"
          output = `file -L "#{ruby_executable}"`.strip
          ruby_arch = output.sub(/.* /, '')
          if ruby_arch == "executable"
            # OS X >= 10.8: something like:
            #   "/opt/ruby-enterprise/bin/ruby: Mach-O 64-bit executable"
            if output =~ /Mach-O 64-bit/
              ruby_arch = "x86_64"
            else
              raise "Cannot autodetect the Ruby interpreter's architecture"
            end
          end
        end
      elsif RUBY_PLATFORM == "java"
        ruby_arch = "java"
      else
        ruby_arch = cpu_architectures[0]
      end
      return "#{ruby_engine}-#{ruby_ext_version}-#{ruby_arch}-#{os_name_simple}"
    end