In Version 7.1, together with GitHub versions of ACL2 before Dec. 3,
2015, you could remove the must-fail wrappers in the book top.lisp,
and the result would be certifiable.  That is, the following version
of top.lisp was certifiable.

(in-package "ACL2")
(include-book "misc/eval" :dir :system)
(include-book "sub1") ; no_port
(include-book "sub2") ; no_port
(include-book "pkg1") ; no_port
(defthm contradiction
  nil
  :hints (("Goal" :use ((:instance a-not-in-acl2-pkg
				   (x (intern$ "B" "MY-PKG")))
			(:instance a-in-acl2-pkg
				   (x (intern$ "B" "MY-PKG"))))))
  :rule-classes nil)
