- Depend on rubygem-cairo instead of deprecated ruby-cairo
Note: i'm not sure this port works correctly, the generated png seems to
always contain: "path '' not found in database"
my ports in the past 3 weeks while ports were broken on any 10.x
machines, which means I'm unable to maintain them. So let people know
that there's no available support for them until things are back to
normal (which also means that anyone with spare time will be able
to fix them without getting approval).
