What do you mean "merge sources"? If you made changes to the code to support MorphOS and want to see them merged in the main codebase, well you need to let us see the changes.
If you're familiar with GitHub, the easiest method is sending us a pull request with your changes (there's a bunch of info in the
Development forum). If not, you can also just post a patch or the modified code or something, although this is more of a hassle to integrate.