One more change by Ken Brown to avoid breaking Cygwin.

src/w32fns.c

@@ -6668,7 +6668,10 @@ Otherwise, if ONLY-DIR-P is non-nil, the user can only select directories.  */)
         /* Strip the dummy filename off the end of the string if we
            added it to select a directory.  */
         if (use_unicode && file_details_w->nFilterIndex == 2
-	    || !use_unicode && file_details_a->nFilterIndex == 2)
+#ifndef NTGUI_UNICODE
+	    || !use_unicode && file_details_a->nFilterIndex == 2
+#endif
+	    )
 	  filename = Ffile_name_directory (filename);
       }
     /* User canceled the dialog without making a selection.  */