[functional tests] Remove dependency on the ThunderChez library.

I've just moved the relevant code into the functional-tests dir.

functional-tests/srfi/s6/basic-string-ports.mzscheme.sls

@@ -0,0 +1,43 @@
+;; Copyright (c) 2009 Derick Eddington.  All rights reserved.
+;; Licensed under an MIT-style license.  My license is in the file
+;; named LICENSE from the original collection this file is distributed
+;; with.  If this file is redistributed with some other collection, my
+;; license must also be included.
+
+#!r6rs
+(library (srfi s6 basic-string-ports)
+  (export
+    (rename (open-string-input-port open-input-string))
+    open-output-string
+    get-output-string)
+  (import
+    (rnrs)
+    (only (scheme base) make-weak-hasheq hash-ref hash-set!))
+  
+  (define accumed-ht (make-weak-hasheq))
+  
+  (define (open-output-string)
+    (letrec ([sop
+              (make-custom-textual-output-port
+               "string-output-port"
+               (lambda (string start count)  ; write!
+                 (when (positive? count)
+                   (let ([al (hash-ref accumed-ht sop)])
+                     (hash-set! accumed-ht sop 
+                       (cons (substring string start (+ start count)) al))))
+                 count)
+               #f  ; get-position  TODO?
+               #f  ; set-position!  TODO?
+               #f  #| closed  TODO? |# )])
+      (hash-set! accumed-ht sop '())
+      sop))
+  
+  (define (get-output-string sop)
+    (if (output-port? sop)
+      (cond [(hash-ref accumed-ht sop #f)
+             => (lambda (al) (apply string-append (reverse al)))]
+            [else
+             (assertion-violation 'get-output-string "not a string-output-port" sop)])
+      (assertion-violation 'get-output-string "not an output-port" sop)))
+
+)

functional-tests/srfi/s6/basic-string-ports.sls

@@ -0,0 +1,20 @@
+;; Copyright (c) 2009 Derick Eddington.  All rights reserved.
+;; Licensed under an MIT-style license.  My license is in the file
+;; named LICENSE from the original collection this file is distributed
+;; with.  If this file is redistributed with some other collection, my
+;; license must also be included.
+
+#!r6rs
+(library (srfi s6 basic-string-ports)
+  (export
+    open-input-string
+    open-output-string
+    get-output-string)
+  (import
+    (rnrs base)
+    (only (rnrs io ports) open-string-input-port)
+    (srfi s6 basic-string-ports compat))
+  
+  (define (open-input-string str)
+    (open-string-input-port str))
+)

functional-tests/srfi/s6/basic-string-ports/compat.chezscheme.sls

@@ -0,0 +1,6 @@
+
+(library (srfi s6 basic-string-ports compat)
+  
+  (export open-output-string get-output-string)
+  
+  (import (only (chezscheme) open-output-string get-output-string)))