Updating code with new Shiva releases

[flippout]

Hey all, just looking for some advice...This seemed like the most appropriate forum.

We're working with XCode-side changes quite a bit for our project. There are a few Shiva headers/.m files we've had to modify for various minor reasons. It's getting unwieldily to update whenever a new engine release happens - I've just been doing it by hand.

I think with a subversion repository (or Perforce for that matter) one could just integrate/merge.

Does anyone have any advice for doing large-scale merges like this in macOS?

Maybe there's some trick I can use with subversion to merge in changes from an unversioned directory?