> They're only BSD-licensing their own core > code and for the time being it's a "illegal" combination of BSD- and > old-MAME-license.
There's nothing illegal about that. It's fine to combine BSD-licensed code with code under the old MAME license, provided the copyright notice is reproduced when it's redistributed in source or binary form and the entire work is distributed under the old MAME license.
(GPL or CDDL can't be combined with old MAME license.)