Some distros install nologin as /usr/sbin/nologin, others as /sbin/nologin. Since we can't really on merged-usr everywhere (where the path wouldn't matter), make the path build time configurable via -Dnologin-path=. Closes #13028
The commit e2c2060f7b makes 'm' lines disturb 'u' lines. This fixes the disturbance.
e2c2060f7b