These are not properly getting added to the library... need to look into why:
$ otool -L /opt/local/lib/libmapnik.dylib
/opt/local/lib/libmapnik.dylib (compatibility version 0.0.0, current version 0.0.0)
/opt/local/lib/libfreetype.6.dylib (compatibility version 10.0.0, current version 10.20.0)
[springmeyer] Ah, pretty easy to add, just specify the ABI versions as linker args.
Done in r1108.
Now a bit a research is needed to determine ABI changes and track their compatibility.