freebsd stable - Mar 2013 - 9.1-stable mergemaster -D fails

running 9.1-STABLE r247548
updating to 9.1-STABLE r248381

When updating to the new version in a zfs beadm environment, mergemaster -D /mnt
fails with install: illegal option -- l

install (1) in the new version has an added -l switch which is used in
bsd.own.mk which in turn is used by mergemaster.

Making mergemaster use the new install(1) fixes the problem.

John Theus
TheUsGroup.com