Update rlgl.h

src/rlgl.h

@@ -21,6 +21,7 @@
 *       Internal buffer (and resources) must be manually unloaded calling rlglClose()
 *
 *   CONFIGURATION:
+*       #define GRAPHICS_API_OPENGL_11_SOFTWARE
 *       #define GRAPHICS_API_OPENGL_11
 *       #define GRAPHICS_API_OPENGL_21
 *       #define GRAPHICS_API_OPENGL_33