with-cwd not releasing memory

[mmc@maruska.dyndns.org (Michal Maruška)]

i have this test code (note the commented version w/o  with-cwd):
$ cat leaks.scm  

#!/usr/bin/scsh \
-e test-files -s
!#

;; read filenames (1 per line) on stdin
(define (test-files args)
  (awk (read-line) (line) ()
    (#t
     ;(if (file-directory? line)
     (let ((dir line))
       ;(directory-files dir #f)       ;  this version works ok

       (with-cwd dir                ;  this version doesn't free memory
         (directory-files "." #f)
         )))))


Now, let's prepare a big fs tree (under  ./test):

$ time (for i in 1 2 3 4 5 6 7 8 9;\
 do  for j in 1 2 3 4 5 6 7 8 9; \
 do for k in 1 2 3 4 5 6 7 8 9;  \
 do for l in 1 2 3 4 5 6 7 8 9; \
 do  mkdir -p test/$i/$j/$k/$l; \
 done;done;done; done;  )

   4,54s user 13,10s system 58% cpu 30,283 total


now to see the problem:
$  find  ./test  -type d | ./leaks.scm  

and  watch the memory consumption (i do w/ mempeak).

w/  scsh 0.6.4  i see it growing to ~ 46 MB   (on bigger tree it keeps growing)

If i try the version  (directory-files dir #f)  it stabilizes at ~21MB.