+ "Unset the multibyte flag of in the current buffer.
+This is a no-op in XEmacs."
+ (when (and (not (featurep 'xemacs))
+ (fboundp 'set-buffer-multibyte))
+ (set-buffer-multibyte nil)))
+
+(defsubst mm-enable-multibyte-mule4 ()
+ "Enable multibyte in the current buffer.
+Only used in Emacs Mule 4."
+ (when (and (not (featurep 'xemacs))
+ (boundp 'default-enable-multibyte-characters)
+ default-enable-multibyte-characters
+ (fboundp 'set-buffer-multibyte)
+ (fboundp 'charsetp)
+ (not (charsetp 'eight-bit-control)))
+ (set-buffer-multibyte t)))
+
+(defsubst mm-disable-multibyte-mule4 ()
+ "Disable multibyte in the current buffer.
+Only used in Emacs Mule 4."
+ (when (and (not (featurep 'xemacs))
+ (fboundp 'set-buffer-multibyte)
+ (fboundp 'charsetp)
+ (not (charsetp 'eight-bit-control)))