I said:

> I'm not a fan of the build infrastructure using su to additional
> users.


"su -s /bin/ksh _fc-cache" is an additional user, and changing their
shell from what is in the passwd file.

That bothers me.

The concept is that the build process runs minimally as root, and moves
all other options to ${BUILDUSER}.  That is privsep.

When you run another user, not for privsep purposes, that is not privsep.

That is why it bothers me.  I cannot see a specific problem being
introduced, but the concept is being changed.