diff: honour -B flag with -q
PR: 278988
Reviewed by: bapt
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D45220
(cherry picked from commit fb623aab3927a6825ff7731198ec2e33426f7607)
(cherry picked from commit 1b7672ed992963e1c79ccc152f4afd72c91481f3)