CMake - including dependencies inside a static library

If you are bound to create a static library, the solution you linked in your original post is probably the best (CMake: include library dependencies in a static library). Using ar or library tools to combine the static libraries seems to be the only way to go. This is a pretty popular question on Stack Overflow and all the answers seem to come down to that.

However, if you are able, the easiest solution by far is to create a shared library and link your static libraries into it (as mentioned by jszpilewski in the comments). Yes, it does mean distributing the shared library for runtime. Whether that is practical or not depends on your project.