It may not be the flex you think it is to leave the SDL2 part as an "exercise for the reader". I don't think it would really affect the size of the data hoard on github if everyone who used an obscure and difficult-to-install library as the basis of their project explained how to get it. Isn't gatekeeping fun and cool?
Here is how you install SDL2 on a Mac (copy and pasted from Google):
brew install sdl2 sdl2_image sdl2_mixer sdl2_ttf