Old meson fails with:
Element not a string: [<Holder: <ExternalProgram 'sh' -> ['/bin/sh']>>, '-c', 'test -n "$DESTDIR" || /bin/journalctl --update-catalog']
I'm doing it as a revert so that it's easy to undo the revert when we require
newer meson. The effect is not so bad, maybe a dozen or so lines about finding
'sh'.
7c22f07cbd