+if(APPLE AND NOT CGRAPH_PATH)
+ set(CGRAPH_PATH "/opt/local/include/graphviz" CACHE PATH "Path to cgraph.h")
+else(APPLE AND NOT CGRAPH_PATH)
+
+ if(EXISTS "/usr/include/graphviz")
+ set(include_graphviz "/usr/include/graphviz")
+ endif(EXISTS "/usr/include/graphviz")
+ if(EXISTS "/usr/local/include/graphviz")
+ set(include_graphviz "/usr/local/include/graphviz")
+ endif(EXISTS "/usr/local/include/graphviz")
+
+ set(CGRAPH_PATH ${include_graphviz} CACHE PATH "Path to cgraph.h")
+endif(APPLE AND NOT CGRAPH_PATH)
+