我正在尝试在 cloud9 中关注此教程here。输入$rails new myproject后，我在尝试$bundle install时收到错误消息。部分错误读取
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
checking for gzdopen() in -lz... no
zlib is missing; necessary for building libxml2
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Make sure that `gem install nokogiri -v '1.6.8.1'` succeeds before bundling.
尝试使用$ gem install nokogiri -v 1.6.8.1进行安装，但获取extconf failed, exit code 1
有没有办法安装nokogirir才能使$bundle install成功？另外，如何在cloud9 IDE中打开mkmf.log文件？我试过了c9 mkmf.log，但它没有用。