I am manually adding the SQLite.swift subproject to my project. As the directions indicated, I copied the .xcodeproj file to my project. This allows me see all the source files (unlike this SO question).
Everything seemed like it was working fine. However, I discovered that the source files of that subproject were not copied to my project. They are still in original location where I downloaded them. Is this by design? What if I want to share my project source code with other people in the future? They won't have the subproject source that is necessary for my project to work.
If I do need to copy the subproject source to my project, then how do I do that?