Issue #16972: Have site.addpackage() consider known paths even when
none are explicitly passed in.
diff --git a/Lib/site.py b/Lib/site.py
index c4c8ea0..732e1c4 100644
--- a/Lib/site.py
+++ b/Lib/site.py
@@ -146,7 +146,7 @@
        and add that to known_paths, or execute it if it starts with 'import '.
     """
     if known_paths is None:
-        _init_pathinfo()
+        known_paths = _init_pathinfo()
         reset = 1
     else:
         reset = 0