http://mamedev.org/?p=422
MAME is now Free and Open Source Software
04 Mar 2016
After 19 years, MAME is now available under an OSI-compliant and FSF-approved
license! Many thanks to all of the contributors who helped this to go as
smoothly as possible!
We have spent the last 10 months trying to contact all people that
contributed to MAME as developers and external contributors and get
information about desired license. We had limited choice to 3 that people
already had dual-license MAME code with.
As a result, a great majority of files (over 90% including core files) are
available under the 3-Clause BSD License but project as a whole is
distributed under the terms of the GNU General Public License, version 2 or
later (GPL-2.0+), since it contains code made available under multiple
GPL-compatible licenses.
If you have contributed to the MAME source code and believe we have not
contacted you, please reach out to us at our contact page.
Please note that MAME is a registered trademark of Nicola Salmoria, and
permission is required to use the "MAME" name, logo or wordmark.
http://www.cnbeta.com/articles/480843.htm
街机模拟器MAME已变身自由软件
流行街机模拟器项目MAME（代表 Multiple Arcade Machine Emulator）修改了许可证，
正式成为自由软件。MAME以前采用的是一个修改版的BSD许可证，禁止商业性质的发行，
因此不符合自由软件定义。自由软件许可证允许你在保证软件自由的条件下自由的发行，
其中包括商业性的出售。
MAME项目联络了所有的代码作者，修改了许可证，它的绝大部分文件采用的是
3-Clause BSD License授权，而整个项目是采用GPL-2.0+许可证授权。
重点来了....
http://mamedev.org/?p=423
Attention for all derivative builds
04 Mar 2016
Please be aware that only files distributed by Mamedev (those available via
the official GitHub) have been subject to the relicensing efforts.
If you maintain a derivative build please be aware that you will have to gain
the correct permission from all contributors for any extra code you have in
your build. Code that was distributed under the previous MAME license can not
be included or linked to MAME from this point forward without being
relicensed, requiring permission from all contributors to that code.
This applies to all derivative builds, including MAMEUI, MESSUI etc. so if
you have a derivative build based upon that code you will need to either
rewrite from scratch or obtain permission from all contributors to the code
in order to relicense.
各分支版本注意（只要你不是 MAME 本家的）
各程式码授权仅提供 MAME 使用，非 MAME 的话请自行重写程式，或者跟各
程式码作者洽询授权。
（影响包含 MAMEUI / MESSUI 等这类将 FrontEnd 整合版）
目前影响范围： MAMEUI MAMEUIFX 不干了，MAME PLUS! 前两版就 Bye 了....
没有影响的就纯 FrontEnd，如 MAME Plus 的 GUI 程式、MAMEUI 作者的 IV/Play 等
后续状况就怎样发展了.....