As you may know, OpenGL (FreeGLUT, acctually) in Linux don’t go fullscreen.
If you try glutGameModeString(“…”); glutEnterGameMode(); You’ll get a non-fullscreen border-less window.
Vote for SDL. But either one will do, you really wont need much knowledge of SDL because it will just create a simple context and return to OpenGL.
I think SDL has more energy and support than the others (you can get feedback faster and search for solutions with better results) and it could support consoles soon.