* lisp/mh-e/mh-acros.el (defun-mh): Check at runtime, not
compile time, whether the target is bound.
* lisp/mh-e/mh-compat.el: Enable compilation. Pull in
mh-acros at compile time.
Authored-by: Glenn Morris <rgm@gnu.org>, Noam Postavsky
<npostavs@users.sourceforge.net>