Pacify byte-compiler in calculator.el

* lisp/calculator.el (calculator-expt): Open-code cl-evenp to
pacify warning “the function ‘cl-evenp’ might not be defined”.
Problem reported by Juanma Barranquero in:
https://lists.gnu.org/r/emacs-devel/2019-11/msg00118.html

1 files changed, 3 insertions, 1 deletions

diff --git a/lisp/calculator.el b/lisp/calculator.el
index fab365d5f28..6c07ee2225d 100644
--- a/lisp/calculator.el
+++ b/lisp/calculator.el
@@ -1620,7 +1620,9 @@ To use this, apply a binary operator (evaluate it), then call this."
   (condition-case nil
       (expt x y)
     (overflow-error
-     (if (or (natnump x) (cl-evenp y))
+     ;; X and Y must be integers, as expt silently returns floating-point
+     ;; infinity on floating-point overflow.
+     (if (or (natnump x) (zerop (logand x 1)))
          1.0e+INF
        -1.0e+INF))))