I work as a videogames programming teacher and videogames developer. Last year I started working in a small C library to teach videogames programming to my students, it's called raylib (http://www.raylib.com). It worked really well with my students and I've continued developing it along this year. Some days ago I released a new version with support for Android devices and Raspberry Pi. raylib also comes with lots of simple code examples (http://www.raylib.com/examples.htm) and some project templates to start mid-size games (https://github.com/raysan5/raylib/tree/master/templates)
In the raylib webpage there is a Windows Installer containing the library, the compiler and a simple code editor for quick installation and usage (really useful for a fast setup), but the library sources, examples and templates also come with RaspberryPi-ready makefiles to be used on Raspberry Pi.
raylib is open source and can be directly downloaded from GitHub repository: https://github.com/raysan5/raylib
I've worked in raylib for more than a year now; I've invested 1000+ hours on its development, getting feedback from more than 80 student and I continuously added required features... raylib worked really well with my students and I think it can be useful for other teachers or Raspberry Pi game developers.
If someone wants to try, just let you know about its existence. Any feedback is welcome!
Note for Moderator: I also posted this info on Education Resources board because raylib is mainly oriented to education but it can also be used for games development. Please, feel free to remove this post if feel convenient.