so that they are correctly calculated as independent.
This avoids issues in bulk builds where the package version was taking
precedence and causing the wrong user package to be depended upon.
* let verbose output to stderr, so that such output is mixed to the command
output (for example, using redirect).
* avoid to use `flock', it is not a part of base.
* useradd
* add skel support
* set homedir properly
* avoid to try dropping from "Users" when uid=gid (pseudo group as user).
* also chgrp gid for created homedir.
* userdel
* catch up error correctly when trying to delete Windows users.
