Am 08.10.23 um 22:36 schrieb Chris Carr:
* Nick McConnell, the upstream maintainer (copied) has confirmed that the remaining files you noted are all GPL-2
compliant (main-ibm.c, snd-cocoa.m, snd-win.h, ui-effect.c and ui-player-properties.c).
For snd-cocoa.m, ui-effect.c, and ui-player-properties.c, I am interested in documenting the copyright holders in d/copyright (just saying "1989-2023 Angband contributors" is not enough). It is clear that they are dual-licensed with GPL-2 being one option.
snd-win.h is licensed under BSD-2-clause (which is GPL-2 compatible), however, the file misses the disclaimer which is referred to in both clauses. Not including it means breaking the license conditions. The same applies to other files: src/sound.h, src/snd-sdl.h, src/message.c, src/message.h, src/z-textblock.c. As I have mentioned, I had only looked at the upstream diff, not all source files.
main-ibm.c does not mention a GPL-2 option. The only license that is mentioned is the Angband license which is not DFSG-free. Upstream should make sure to mention GPL-2 as an alternative.