message: fix MSAA w/ multisampled_render_to_texture on Mali
  according to the gl spec, we can't mix the EXT versions of
  glRenderbufferStorageMultisample/glFramebufferMultisample with
  the regular versions. Other drivers are more permissive.
  When allocating a renderbuffer and the extention is supported, we always
  use it.
diff: @@ -1074,10 +1074,16 @@ void OpenGLDriver::renderBufferStorage(GLuint rbo, GLenum internalformat, uint32
  uint32_t height, uint8_t samples) const noexcept {
  glBindRenderbuffer(GL_RENDERBUFFER, rbo);
  if (samples > 1) {
  - // We don't support "implicit" (i.e. EXT_multisampled_render_to_texture) renderbuffer
  - // (in practice this means that a texture must be marked 'SAMPLEABLE' if 'implicit'
  - // resolves are desired.
  +#ifdef GL_EXT_multisampled_render_to_texture
  + auto& gl = mContext;
  + if (gl.ext.EXT_multisampled_render_to_texture ||
  + gl.ext.EXT_multisampled_render_to_texture2) {
  + glext::glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, internalformat, width, height);
  + } else
  +#endif
  + {
  glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, internalformat, width, height);
  + }
  } else {
  glRenderbufferStorage(GL_RENDERBUFFER, internalformat, width, height);
  }
  