32 #include <SFML/Config.h>    39 #if defined(CSFML_SYSTEM_WINDOWS)    45 #elif defined(CSFML_SYSTEM_LINUX) || defined(CSFML_SYSTEM_FREEBSD)    50 #elif defined(CSFML_SYSTEM_MACOS)    52     #include <OpenGL/gl.h>    53     #include <OpenGL/glu.h>    58 #endif // SFML_OPENGL_H