Help with SHARED_LIBS

Hello everyone!

I'm trying to make a port of Ringdove pcb tools (pcb-rnd, camv-rnd)
and I'm working with the needed common part librnd.

Currently I'm stuck in SHARED_LIBS. How should I manage the versions?
Ringdove programs don't use libtool and currently I have in my PLIST
for example

@so lib/librnd-poly.so
lib/librnd-poly.so.3
@bin lib/librnd-poly.so.3.0.0-dev

Should I set up variables for the library version and try to override
the filenames or somehow copy them or what kind of good options do I
have to get this right?

Also some reference port would be nice to know which doesn't use
libtool and is still small and simple.

Homepage of biggest tool pcb-rnd: http://repo.hu/projects/pcb-rnd/

Best regards,
Hannu Vuolasaho