SDL currently has no way of actually creating a context in OSX without hardcoding in the values, I tried to create a  4.1 context it appears that in SDL they don't allow it to happen either. I tried to use just
SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
and SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_COMPATIBILITY); without hard coding in the values it did not work. SDL requires that you need to set the context version numbers.
I think if we were to do this, we can hard code in the values. Then allow developers to override the create context call with a configuration, if they really must. Otherwise we would be restricting OSX users to only Opengl 2.1 by default