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.
vsftpd improvements:
- intorduce one declarative list of options
- make docummentation strings more understandable and add missing options
such as SSL/TLS support
- Use environment.etc."vsftpd".text because I can't think about any
reason why a shell script should be used.
That code was written in 2009.
