Update rlgl.h

Author: raysan5

src/rlgl.h

@@ -870,6 +870,7 @@ RLAPI void rlLoadDrawQuad(void);     // Load and draw a quad
 #elif defined(GRAPHICS_API_OPENGL_ES2)
     // NOTE: OpenGL ES 2.0 can be enabled on Desktop platforms,
     // in that case, functions are loaded from a custom glad for OpenGL ES 2.0
+    // TODO: OpenGL ES 2.0 support shouldn't be platform-dependant, neither require GLAD
     #if defined(PLATFORM_DESKTOP_GLFW) || defined(PLATFORM_DESKTOP_SDL)
         #define GLAD_GLES2_IMPLEMENTATION
         #include "external/glad_gles2.h"