Building native extensions.  This could take a while...
ERROR:  Error installing nokogiri:
        ERROR: Failed to build gem native extension.

/Users/me/.rvm/ree-1.8.7-2009.10/bin/ruby extconf.rb --with-xml2-include=/usr/local/include/libxml2 --with-xml2-lib=/usr/local/lib
checking for iconv.h in /opt/local/include/,/usr/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/Users/me/.rvm/ree-1.8.7-2009.10/include,/Users/me/.rvm/ree-1.8.7-2009.10/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for libxml/parser.h in /opt/local/include/,/usr/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/Users/me/.rvm/ree-1.8.7-2009.10/include,/Users/me/.rvm/ree-1.8.7-2009.10/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for libxslt/xslt.h in /opt/local/include/,/usr/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/Users/me/.rvm/ree-1.8.7-2009.10/include,/Users/me/.rvm/ree-1.8.7-2009.10/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for libexslt/exslt.h in /opt/local/include/,/usr/local/include/libxml2,/opt/local/include,/opt/local/include,/opt/local/include/libxml2,/usr/local/include,/usr/local/include/libxml2,/Users/me/.rvm/ree-1.8.7-2009.10/include,/Users/me/.rvm/ree-1.8.7-2009.10/include/libxml2,/usr/include,/usr/include/libxml2... yes
checking for xmlParseDoc() in -lxml2... no
libxml2 is missing.  try 'port install libxml2' or 'yum install 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.