[sudo-users] /etc/sudoers.d macOS 10.12.4

[Todd C. Miller]

The first thing to check is that /etc/sudoers has something
like the following at the bottom:

## Read drop-in files from /private/etc/sudoers.d
## (the '#' here does not indicate a comment)
#includedir /private/etc/sudoers.d

That will parse extra sudoers format files in /etc/sudoers.d
(which should already exist).

Be aware that sudo will skip file names that end in `~' or contain
a `.' character to avoid causing problems with package manager or
editor temporary/backup files.

 - todd