nixos/nixseparatedebuginfod: fix compatibility with Nix 2.3

Appending to options with the `extra-` prefix was added in Nix 2.4,
which makes config validation fail on this version without the guard.

Change-Id: Ie253978dbaf00b228fecc08698a3dcc01cd2d82b

V ff990ea6 a51f0948

Changed files
+3 -1
nixos
modules
services
+3 -1
nixos/modules/services/development/nixseparatedebuginfod.nix
···
users.groups.nixseparatedebuginfod = { };
-
nix.settings.extra-allowed-users = [ "nixseparatedebuginfod" ];
environment.variables.DEBUGINFOD_URLS = "http://${url}";
···
users.groups.nixseparatedebuginfod = { };
+
nix.settings = lib.optionalAttrs (lib.versionAtLeast config.nix.package.version "2.4") {
+
extra-allowed-users = [ "nixseparatedebuginfod" ];
+
};
environment.variables.DEBUGINFOD_URLS = "http://${url}";