This flake exposes two packages, corresponding to the specific and generic zen versions.
The generic version maximizes compatibility with old CPUs and kernels by compiling it with some
lower common denominator CFLAGS, the specific one targets newer CPUs and kernels but it may not
work in your case.
The default package is the specific one for backwards compatibility with older versions of the flake.
Then in the configuration.nix in the environment.systemPackages add one of: