[functional tests] Remove dependency on the ThunderChez library.

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

functional-tests/srfi/private/OS-id-features.sls

@@ -0,0 +1,25 @@
+;; 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 private OS-id-features)
+  (export
+    OS-id-features)
+  (import 
+    (rnrs))
+
+  (define (OS-id-features OS-id features-alist)
+    (define OS-id-len (string-length OS-id))
+    (define (OS-id-contains? str)
+      (define str-len (string-length str))
+      (let loop ((i 0))
+        (and (<= (+ i str-len) OS-id-len)
+             (or (string-ci=? str (substring OS-id i (+ i str-len)))
+                 (loop (+ 1 i))))))
+    (apply append
+           (map cdr (filter (lambda (x) (OS-id-contains? (car x)))
+                            features-alist))))
+)