I have no experience with Xcode or QtCreator, so I can’t say anything about that.
But i do not think at all that CMake is overkill, it’s the opposite. It is exactly what OF needs. CMake is even advisable for very small projects with a single file and the bigger it gets the more important a proper build system gets.
Makefiles (or at least writing them manually) is absolutely deprecated. You can achieve the same thing with CMake with 10 times less code and it works out of the box on any platform.
If you have proper cmake support, everything would be easier. It would find system packages, dependencies, link them for you, build all the files, install them into your system in an installation directory and i recently learned that you can even create installers for any platform using native cmake. Installers for distributing OF applications is currently entirely unsupported, right? With CMake it could be done with a single command, building installers for windows, and deb, rpm and dmg packages for any unix systems. Out of the box.
Seriously, I don’t quite know how you package OF in the github releases (where you’re getting the precompiled binaries from), but if you had cmake you wouldn’t need any of that. It just works on any system.
It wouldn’t even change the project generator a lot. If you insist on keeping the project generator, it could still be used with CMake. There could be an option that generates a CMake project that has the opposite structure as usual, so it would generate the project root as the root, in any external folder, and includes a CMake file that then pulls OF as a dependency and links it. It can even automatically download the dependencies.
Also, there are no absolute paths whatsoever. As @burton said, it opens many many many doors for other projects, build systems, and even a package manager like conan. How lovely would it be to have OF in Conan… On the other hand the only doors being closed are weird Makelist errors and linking errors. Additionally it’s quite important for Continuous Integration. If OF has that at all, it would make it 1000 times easier and CMake could do ALL of the packaging and releasing work and even create a nightly build for github releases, with all dependencies included. And for the end users, it’s just 3 additional lines to bundle everything into an installer so you can distribute your app.
I do not even want to sound like i’m just praising CMake, but I think OF is seriously missing any proper build system. The code is there but it can’t be built easily. Without offending anyone, I get the feeling you haven’t worked with a proper build system before and do not know how easy everything could get