I was only able to build on MacOS after removing the following lines from ./CMakeLists.txt and ./samples/CMakeLists.txt:

elseif (UNIX AND APPLE)
    link_libraries("framework")

It may be worth noting that, contrary to the docs, this works regardless of whether I use SDL2.framework (installed at /Library/Frameworks) or the homebrew version.

I'm submitting this as an issue rather than a pull request because I don't yet understand Tilengine well enough to:

1. understand what purpose these lines serve
2. know whether they're still required
3. ensure removing them won't break something (I've tried a few of the samples; they seem to run fine)

Happy to make a PR if needed.