added a note about the ignore_dangling_symlinks option
diff --git a/Lib/shutil.py b/Lib/shutil.py
index 465f841..8890d24 100644
--- a/Lib/shutil.py
+++ b/Lib/shutil.py
@@ -161,8 +161,8 @@
     an Error exception at the end of the copy process.
 
     You can set the optional ignore_dangling_symlinks flag to true if you
-    want to silence this exception.
-
+    want to silence this exception. Notice that this has no effect on
+    platforms that don't support os.symlink.
 
     The optional ignore argument is a callable. If given, it
     is called with the `src` parameter, which is the directory