currently `libGL.so.1` just happens to be in the closure via `cairo`, but that's no longer the case in Nixpkgs 23.11
...and clean up the disabling of filesystem-related unit tests. ...and, surprise! Setting `ContinuousIntegrationBuild` was enough to fix the remaining r13y problems. I spent hours pre-merge trying random things, so that's irritating.
fixes b47b4d63b
b47b4d63b