It can be as easy as hitting "make" or it can be as hard as doing a rewrite from scratch *doh*

It really depends on the quality of the code, what was used on the OS4 side and what constitutes a "MorphOS-port".

Some people are o.k. with having to hunt down some crappy 68k ClassAct/ReAction to call it working, others expect it do be done in the right way.