Unless your USB stick has an extremely low capacity, just about any Linux distribution should fit on it. For example, you can install Ubuntu 15.10 to an 8 GB USB stick just fine. If you're just looking for a minimal install, there are plenty: Arch Linux, Puppy Linux, Absolute Linux, Trisquel Mini, Lubuntu... If you want really small, then there's always Damn Small Linux (though the last release was 8 years ago) or CorePlus/TinyCore.
Similar to my first point, you can install gcc on just about any Linux distribution, and the same should be true for OpenGL development libraries if needed.
Though this may not be a popular choice, you can compile C/C++ and OpenGL on Windows, so I'm not sure what the "need" for a Linux USB stick is here.
Lastly, this question really seems like it might be subjective.