SRFI 41 library doesn't export required variable

What steps will reproduce the problem?
Run the following script

(import (rnrs) (srfi :41))

(define-stream (isort lt? strm)
  (define-stream (insert strm x)
    (stream-match strm
      (() (stream x))
      ((y . ys) (if (lt? y x)
                    (stream-cons y (insert ys x))
                    (stream-cons x strm)))))
  (stream-fold insert stream-null strm))

What is the expected output? What do you see instead?
Compile properly

launching debugger...
 Syntax error
      who : invalid reference
  message : No binding available for [=>] in library (srfi :41 streams derived)
     form : =>

What version of the product are you using? On what operating system?
% nmosh -v
Mosh R6RS scheme interpreter, version 0.2.7 (mosh-0.2.7 Tue, 14 Jun 2011 
07:00:31 +0900)

Please provide any additional information below.
lib/srfi/%3a41/streams/derived.sls doesn't import '=>' and 'stream-match' is 
using it.

Original issue reported on code.google.com by ktakash...@gmail.com on 17 Oct 2013 at 8:39

seanjensengrey / mosh-scheme

SRFI 41 library doesn't export required variable #238