As of 2.2.2 stable runtime release you can now record GIFs in game using any surface. Here I show setting that up in a simple way using the application surface to record the whole game.
Attached to this post is the script as run in the post-draw event. You'll need to swap out the size macros RESOLUTION_W and H for your own sizes and remember to declare gifRecord in the create event.
Hope you enjoy this! Public release on Friday.