Initializes SDL. This should be called before all other SDL functions. The flags parameter specifies what part(s) of SDL to initialize.
| SDL_INIT_TIMER | Initializes the timer subsystem. |
| SDL_INIT_AUDIO | Initializes the audio subsystem. |
| SDL_INIT_VIDEO | Initializes the video subsystem. |
| SDL_INIT_CDROM | Initializes the cdrom subsystem. |
| SDL_INIT_JOYSTICK | Initializes the joystick subsystem. |
| SDL_INIT_EVERYTHING | Initialize all of the above. |
| SDL_INIT_NOPARACHUTE | Prevents SDL from catching fatal signals. |
| SDL_INIT_EVENTTHREAD |