Lbfix
Logical bit fix. (lbfix b) is logically identical to (bfix
b) but executes as the identity. It requires (bitp b) as a guard, and
expands to just b.
Macro: lbfix
(defmacro lbfix (x)
(cons 'mbe
(cons ':logic
(cons (cons 'bfix (cons x 'nil))
(cons ':exec (cons x 'nil))))))
