Add code to check `base64-encode-string' is builtin or not again.

diff --git a/mel.el b/mel.el
index 226a9fb..277bf6a 100644 (file)
--- a/mel.el
+++ b/mel.el
@@ -96,7 +96,8 @@ Content-Transfer-Encoding for it."
 
 (mel-define-backend "binary" ("8bit"))
 
-(when (fboundp 'base64-encode-string)
+(when (and (fboundp 'base64-encode-string)
+          (subrp (symbol-function 'base64-encode-string)))
   (mel-define-backend "base64")
   (mel-define-method-function (mime-encode-string string (nil "base64"))
                              'base64-encode-string)