deploy@prototype:/web/apps/vitality$ sudo gem install nokogiri
Building native extensions.  This could take a while...
ERROR:  Error installing nokogiri:
	ERROR: Failed to build gem native extension.

rake RUBYARCHDIR=/usr/lib/ruby/gems/1.8/gems/nokogiri-1.0.5/lib RUBYLIBDIR=/usr/lib/ruby/gems/1.8/gems/nokogiri-1.0.5/lib
/usr/lib/ruby/gems/1.8/gems/rake-0.8.3/lib/rake/gempackagetask.rb:13:Warning: Gem::manage_gems is deprecated and will be removed on or after March 2009.
(in /usr/lib/ruby/gems/1.8/gems/nokogiri-1.0.5)
checking for xmlParseDoc() in -lxml2... no
checking for xsltParseStylesheetDoc() in -lxslt... no
checking for #include <libxml/xmlversion.h>
... no
need libxml
*** extconf.rb failed ***