Add __printflike's where possible and fix all related bugs & issues.
mdoc cleanup: Fix some column lists (add .It).
getent(1): Raise WARNS to 6.
Bring the getent(1) program in from FreeBSD and link it into the build.Submitted-by: Matthias Schmidt <schmidtm@mathematik.uni-marburg.de>Obtained-from: FreeBSD