Primitive E module for an XOR gate.
We use this to implement vl2014::*vl-1-bit-xor*.
Definition: *esim-xor*
(defconst *esim-xor* '(:n *esim-xor* :x (:out ((|out| xor |a| |b|))) :i ((|a|) (|b|)) :o ((|out|))))
