The `-m` may be overzealous. I have some sites running as users with `/sbin/nologin` for a shell, and this allows running a command as those users, though without some typical environment variables. This is probably wrong. Maybe I should be doing something else to limit shell access for those users, and the su arg should instead be `-`.
--[[schmonz]]
+
+> To get some real-world and very cross-platform testing, I've committed
+> a conservative version of this patch, with `-` in place of `-m`, to
+> pkgsrc's ikiwiki package (rev 3.20180311nb1), and will report back. In
+> the meanwhile, would this change cause any obvious regressions on
+> Debian? --[[schmonz]]