Prefer oddp/evenp to open-coding in a few more cases

* lisp/arc-mode.el (archive-zip-summarize):
* lisp/cus-edit.el (setopt):
* lisp/isearch.el (isearch-backslash):
* lisp/simple.el (blink-paren-post-self-insert-function):
* lisp/subr.el (setq-local, buffer-local-set-state):
* lisp/term.el (term-within-quotes):
* test/src/data-tests.el (test-bool-vector-bv-from-hex-string): Use
oddp/evenp instead of open-coding them.
Reported by Pip Cet <pipcet@protonmail.com>.

lisp/arc-mode.el

@@ -2090,8 +2090,7 @@ This doesn't recover lost files, it just undoes changes in the buffer itself."
 			    ((memq creator '(0 5 6 7 10 11 15)) ; Dos etc.
 			     (logior ?\444
 				     (if isdir (logior 16384 ?\111) 0)
-				     (if (zerop
-					  (logand 1 (get-byte (+ p 38))))
+				     (if (evenp (get-byte (+ p 38)))
 					 ?\222 0)))
 			    (t nil)))
 	     (fiddle  (and archive-zip-case-fiddle

lisp/cus-edit.el

@@ -1060,7 +1060,7 @@ even if it doesn't match the type.)
 
 \(fn [VARIABLE VALUE]...)"
   (declare (debug setq))
-  (unless (zerop (mod (length pairs) 2))
+  (unless (evenp (length pairs))
     (error "PAIRS must have an even number of variable/value members"))
   (let ((expr nil))
     (while pairs

lisp/isearch.el

@@ -2893,7 +2893,7 @@ The command accepts Unicode names like \"smiling face\" or
 
 (defun isearch-backslash (str)
   "Return t if STR ends in an odd number of backslashes."
-  (= (mod (- (length str) (string-match "\\\\*\\'" str)) 2) 1))
+  (oddp (- (length str) (string-match "\\\\*\\'" str))))
 
 (defun isearch-fallback (want-backslash &optional allow-invalid to-barrier)
   "Return point to previous successful match to allow regexp liberalization.

lisp/simple.el

@@ -9622,11 +9622,11 @@ More precisely, a char with closeparen syntax is self-inserted.")
 	     ;; Verify an even number of quoting characters precede the close.
              ;; FIXME: Also check if this parenthesis closes a comment as
              ;; can happen in Pascal and SML.
-	     (= 1 (logand 1 (- (point)
-			       (save-excursion
-				 (forward-char -1)
-				 (skip-syntax-backward "/\\")
-				 (point))))))
+	     (oddp (- (point)
+		      (save-excursion
+			(forward-char -1)
+			(skip-syntax-backward "/\\")
+			(point)))))
     (funcall blink-paren-function)))
 
 (put 'blink-paren-post-self-insert-function 'priority 100)

lisp/subr.el

@@ -176,7 +176,7 @@ pair.
 
 \(fn [VARIABLE VALUE]...)"
   (declare (debug setq))
-  (unless (zerop (mod (length pairs) 2))
+  (unless (evenp (length pairs))
     (error "PAIRS must have an even number of variable/value members"))
   (let ((expr nil))
     (while pairs
@@ -217,7 +217,7 @@ in order to restore the state of the local variables set via this macro.
 
 \(fn [VARIABLE VALUE]...)"
   (declare (debug setq))
-  (unless (zerop (mod (length pairs) 2))
+  (unless (evenp (length pairs))
     (error "PAIRS must have an even number of variable/value members"))
   `(prog1
        (buffer-local-set-state--get ',pairs)

lisp/term.el

@@ -2181,7 +2181,7 @@ A useful command to bind to SPC.  See `term-replace-by-expanded-history'."
 Quotes are single and double."
   (let ((countsq (term-how-many-region "\\(^\\|[^\\]\\)'" beg end))
 	(countdq (term-how-many-region "\\(^\\|[^\\]\\)\"" beg end)))
-    (or (= (mod countsq 2) 1) (= (mod countdq 2) 1))))
+    (or (oddp countsq) (oddp countdq))))
 
 (defun term-how-many-region (regexp beg end)
   "Return number of matches for REGEXP from BEG to END."

test/src/data-tests.el

@@ -184,7 +184,7 @@ this is exactly representable and is greater than
     (let ((i 0))
       (dolist (n (nreverse nibbles))
         (dotimes (_ 4)
-          (aset bv i (> (logand 1 n) 0))
+          (aset bv i (oddp n))
           (cl-incf i)
           (setf n (ash n -1)))))
     bv))