The description is clearly what effect the knob has when set, so the
additional text was unnecessary.
Reviewed by: jhb, se
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D29583
(default: WITH_GH_BC) and 12-STABLE (default: WITHOUT_GH_BC).
Since the new implementation of bc and dc is optionally available in
12-STABLE, I intend to MFC these descriptions for inclusion in 12.2.
MFC after: 3 days