Adaptation of a bit outdated cl-graphviz library (http://common-lisp.net/project/cl-graphviz/index-old.shtml page on cliki: http://www.cliki.net/cl-graphviz) written by Attila Lendvai (http://www.cliki.net/Attila%20Lendvai) to the modern version of libgvc.so.6 (graphviz 2.28 library).
May be again outdated. Check out hu.dwim.graphviz for an alternative integration solution.