gem install时报错，no such file to load -- zlib

通过gem 安装mysql库时，报告：

#gem install mysql
ERROR:  Loading command: install (LoadError)
no such file to load -- zlib
ERROR:  While executing gem ... (NameError)
uninitialized constant Gem::Commands::InstallCommand

解决办法：

进入ruby源码文件夹
安装ruby自身提供的zlib包
#cd ext/zlib
#ruby ./extconf.rb
#make
#make install

问题解决。