Yes, separate compilation, and since your language, as I understand it, will support receiving and using scraps from wherever, you'll have to deal with it too unless you insist on strictly source-code sharing only.

You see, those are eternal (well, perennial) problems with distributed code management and every language/computing platform has to deal with them somehow, so that's why I'm interested in what your approach is, especially so since you aim to "solve the software sharability problem".