Mac: Immediately update current OpenGL context's shape. Previously we were postponing our -[NSOpenGLContext update] call to the next SDL_GL_SwapWindow, even if the context was current on the current thread. This changes it so that we will do the update immediately if it's the current context. If you're rendering on another thread, you need to call SDL_GL_SwapWindow once after a resize event to ensure your drawable will produce non-garbage data. Bug: https://bugzilla.libsdl.org/show_bug.cgi?id=2339