no such file to load - zlib uninitialized constant Gem:Commands:InstallCom

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


    uninitialized constant Gem::Commands::InstallCommand

解决办法是：

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