Due to a X locking bug in NWN, NWN fails an assertion when libX11 was compiled with xcb support. As suggested in /opt/nwn/nwn start script, the "./lib" component of the library search path should be removed when libX11 was compiled with xcb support so NWN uses the system-supplied libSDL - at least there should be a clear notice about this somewhere (maybe as an ewarn in the ebuild). Probably the NWN ebuild should depend on libSDL in this case (means libX11 compiled with USE="xcb"). Reproducible: Always
Thinking about it, it looks more like a bug in the game-supplied libSDL... *sigh*
Please, unmask and try nwn-1.68-r2 which should fix that for you. If you can try with and without xcb on x86 and amd64 that would be ideal. Denis.
It works now, also one of the segfault problems is gone (the other was related due to an incomplete installation). I did not test running with beryl though which didn't work well with the supplied libSDL. I'll give feedback about that later.
nwn-1.68-r3 was just committed, has this fix (and others), and is now unmasked. Enjoy. Denis.
I think this can be closed as the new bundled libSDL solves the problem. Reopen if problems persist for others. Fixed it with USE=xcb on x86 for me.