We'd likely be better served by converting these to the equivalent mem*
calls, but just kill the knob for now. The b* macros being defined get
in the way of _FORTIFY_SOURCE.
Reviewed by: imp, markj
Differential Revision: https://reviews.freebsd.org/D32235
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.