Haze continues to make the same fundamental mistake: he doesn't understand multiple licensing. When Aaron made the core stuff BSD (which allowed CD-i Emulator, DEMUL, and WinUAE to use his code to load CHDs, by the way) it was still also shipped in MAME under the MAME license. BSD only applies once you remove it from MAME; within MAME the license of MAME always applies and there is no issue combining it with other MAME code.
The same thing happened when Olivier and I relicensed our YMF278B sound core as MAME and LGPL v2.1: in MAME it's under the MAME license and can be combined with any other MAME file no problem. OpenMSX was then able to use the code for MoonSound emulation, subject it to a lot more test cases than we had available in MAME, and send us back a stack of bugfixes which made MAME sound better. That's a true win-win.