* plugin-runner.c (main): Bug fix; do not ignore return value of
                          setgid().
* plugins.d/mandos-client.c (main): Bug fix: sleep() takes an unsigned
                                    int, not an int.
* plugins.d/plymouth.c (exec_and_wait, getargv, main/plymouthd_argv):
                       Add more const-ness to the argv pointer.