Bitmaps in ScrollWindow and Robot code are managed by the kernel
and not by game scripts, although they must be able to be
referenced through a reg_t. To prevent incorrect GC of bitmaps
that are in use but not referenced by any game script, explicit
memory management of hunk entries can be enabled.
This kernel call seems only to be used by KQ7 1.51 (which was
Windows-only) to send warnings to the user.
It was easy enough to do a basic implementation in the ScummVM
GUI rather than just make it an empty call, so now it is a thing.