The G15 builds will definitely not work. You not only need the correct build for your camera, it actually has to also match the firmware version installed in your camera.
The G16 uses the newer DIGIC6 chipset and the standard CHDK porting tools and methods don't work with those cameras. It could be a long time before somebody with access to the camera and the necessary skills has the time and interest in creating a port. Sorry.
More info about the CHDK porting process here :link> CHDK FAQ : My camera isn't ported yet