handle = Ctl.as_Resource(ctl)
ctl = Ctl.as_Control(handle)
and similarly for List, Menu, TE. The old handle.as_Control() methods are
still there for backward compatability.
blacklisted, because they are not available in classic 68k programs,
and bgen doesn't have a way to put #ifdef/#endif in the generated
code. For now we only implement calls that work on all three models.