Gail will be loaded if the whole system's accessibility is enabled. And I am not sure if your application wants to depend on gail. Evolution met the same problem. You can take a look at ea-combo-button.c in Evolution. e-combo-button is based on GtkButton, ea-combo-button is based on gailbutton and Evolution is not depend on gail. Just inherit it run-time.
Thanks, Li. That helped. I didn't realize that I could look up the AtkObject factory for a type and then use the factory to retrieve the accessible type. That gets around the whole issue of not being able to access gail's symbols. I now have the GailWidget functionality back (the widget still doesn't provide any meaningful accessibility because I haven't written an AtkTextIface implementation yet.)
I'll write again if I run into anything else that I can't figure out. -Mike