anchor.diff:  
   ;;;; ** Converting strings to/from foreign encodings
   
  +(declaim (inline string-to-octets))
   (defun string-to-octets (string encoding)
     "Convert STRING, a list string, a vector of bytes according to ENCODING.
   
  
positive.code: 
  #+(and sbcl sb-unicode)
  (progn
    (defun encoding-keyword-to-native (encoding)
      (case encoding
        (:utf-8 :utf8)
        (:utf-16 :utf16)
  
negative.code: 
  #-(or (and sbcl sb-unicode) (and clisp unicode))
  (progn
    (defun %encoding-keyword-to-native (encoding)
      encoding)
    
    (defun %string-to-octets (string encoding)
      (declare (ignore encoding))
      (map-into (make-array (length string) :element-type 'unsigned-byte)
  