libxml2 is missing - install nokogiri - centos

[cg@centos63 webbot]$ sudo yum install libxml2-devel libxslt-devel




[cg@centos63 webbot]$ sudo /usr/local/bin/gem install nokogiri
Building native extensions.  This could take a while...
Successfully installed nokogiri-1.5.5
1 gem installed
Installing ri documentation for nokogiri-1.5.5...
Installing RDoc documentation for nokogiri-1.5.5...