Nokogiri gem on FreeBSD, libiconv missing error

If you try to install the nokogiri gem on freebsd you may get the following error message:

libiconv is missing. please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.

In that case it should suffice to use the following command to install the gem:

% gem install nokogiri -v 'DESIRED_VERSION' -- --with-iconv-lib=/usr/local/lib --with-iconv-include=/usr/local/include

If you get further error messages complaining about libxslt or libxml you may need a couple more options:

% gem install nokogiri -v 'DESIRED_VERSION' -- --use-system-libraries \
  --with-iconv-lib=/usr/local/lib --with-iconv-include=/usr/local/include \
  --with-xml2-lib=/usr/local/lib --with-xml2-include=/usr/local/include/libxml2/libxml \
  --with-xslt-lib=/usr/local/lib --with-xslt-include=/usr/local/include/libxslt