Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.
Reviewed by: ru
Approved by: philip, ed (mentors)
whether a named utility should behave in FreeBSD 4.x-compatible mode
or in a standard mode (default standard). The configuration is done
malloc(3)-style, with either an environment variable or a symlink.
Update expr(1) to use this new interface.