--- a/lisp/mule/mule-cmds.el	Fri Jul 24 14:48:46 2015 +0100
+++ b/lisp/mule/mule-cmds.el	Thu Dec 16 18:48:58 2021 +0000
@@ -1305,7 +1305,7 @@
       ;; that follow Unix conventions, but also MS Windows locales.
       ;; So set the MS Windows locale, and then try to find a Unix
       ;; locale.
-      (when (eq system-type 'cygwin32)
+      (when (memq system-type '(cygwin32 cygwin64))
 	(mswindows-get-and-set-locale-from-langenv langenv))
       (let ((locs (get-language-info langenv 'locale)))
 	(dolist (loc (if (listp locs) locs (list locs)))
@@ -1380,7 +1380,7 @@
       ;;     to edit ~/.xemacs/init.el. Aidan Kehoe, Sun Nov 26 18:11:31 CET
       ;;     2006. OS X uses an almost-normal-form version of UTF-8. 
 
-      (unless (memq system-type '(windows-nt cygwin32))
+      (unless (memq system-type '(windows-nt cygwin32 cygwin64))
 	(set-default-buffer-file-coding-system
 	 (maybe-change-coding-system-with-eol default-coding eol-type))))
     ;; (setq default-sendmail-coding-system default-coding)
@@ -1452,7 +1452,7 @@
 
   (let (langenv)
     ;; under ms windows (any):
-    (if (memq system-type '(windows-nt cygwin32))
+    (if (memq system-type '(windows-nt cygwin32 cygwin64))
       (let ((userdef (declare-fboundp (mswindows-user-default-locale)))
 	    (sysdef (declare-fboundp (mswindows-system-default-locale))))
 	;; (1) current langenv comes from user-default locale.