[plt-scheme] _bytes in FFI

Hi there,

It looks like the following:

(require (lib "foreign.ss")) (unsafe!)

(define libcrypt (ffi-lib "libcrypt"))

(define crypt
   (get-ffi-obj "crypt" libcrypt (_fun _string _string -> _bytes)))


will not work outside a module, at least on 360 on MacOS. I get:

procedure application: expected procedure, given: #f; arguments were:  
#<struct:fun-syntax> #<syntax:6:57>

The problem goes away if I replace _bytes with _pointer or if I wrap  
the whole thing in a module.

What gives?

-pp