I updated to the developer release of Lion and noticed I couldn\'t start rails apps anymore. Whenever I try to sudo bundle install, I get the following error:>
sudo bundle install
I had similar problem, and after installing XCode 4.1, I also had to do the following command:
sudo port upgrade libxml2 libxslt
After that Nokogiri built without problems.
More info: http://tektastic.com/2011/07/ruby-mac-ports-and-os-x-lion.html