"batch" is a shell script so invoking it via setuid wrapper never worked
anyway. (The kernel drops perms on executables with shebang.) A previous
nixpkgs commit made "batch" invoke the NixOS setuid "at" wrapper to gain
needed privileges.
Thanks to @yesbox for noticing.
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
That is, you can say
security.pam.services.sshd = { options... };
instead of
security.pam.services = [ { name = "sshd"; options... } ];
making it easier to override PAM settings from other modules.
