lanmap will not emerge because it depends on an old version of graphviz which is no longer in the tree. Perhaps lanmap also should also be removed from the tree. There is a bug to add lanmap2 with bug 354313, but even lanmap2 hasn't seen a commit in 4 years, and it never had an actual release. Reproducible: Always
are you referring to it failing to build with newer releases? Can you provide the build.log and emerge --info output please?