io: repair directory-list for Windows

racket/src/io/Makefile

@@ -23,6 +23,7 @@ GLOBALS = --no-global \
           ++global-ok "string->number?" \
           ++global-ok "printable-regexp?" \
           ++global-ok do-global-print \
+          ++global-ok simplify-path/dl \
           ++global-ok exec-file \
           ++global-ok run-file \
           ++global-ok collects-dir \

racket/src/io/file/main.rkt

@@ -36,7 +36,9 @@
          filesystem-root-list
 
          ;; For the expander to register `maybe-raise-missing-module`:
-         set-maybe-raise-missing-module!)
+         set-maybe-raise-missing-module!
+	 ;; To resolve a cycle with the definition of `simplify-path`
+	 set-simplify-path-for-directory-list!)
 
 (define/who (directory-exists? p)
   (check who path-string? p)
@@ -65,9 +67,18 @@
                                         "")
                                     (host-> host-path)))))
 
+(define simplify-path/dl (lambda (p) p))
+(define (set-simplify-path-for-directory-list! proc)
+  (set! simplify-path/dl proc))
+
 (define/who (directory-list [p (current-directory)])
   (check who path-string? p)
-  (define host-path (->host p who '(read)))
+  (define host-path/initial (->host p who '(read)))
+  (define host-path (case (system-type)
+		      [(windows)
+		       ;; Need to avoid "." and "..", so simplify
+		       (->host (simplify-path/dl (host-> host-path/initial)) #f '())]
+		      [else host-path/initial]))
   (atomically
    (call-with-resource
     (rktio_directory_list_start rktio host-path)

racket/src/io/path/simplify.rkt

@@ -106,6 +106,8 @@
            (path->directory-path simpler-p)
            simpler-p)])]))
 
+(void (set-simplify-path-for-directory-list! simplify-path))
+
 ;; ----------------------------------------
 
 ;; Quick check for whether the path is already simple: