Issue #12599: Be more strict in accepting None vs. a false-like object
in importlib.

Thanks to PJE for pointing out the issue and Nick Coghlan for filing
the bug.
diff --git a/Python/importlib.h b/Python/importlib.h
index 3a03c46..392b941 100644
--- a/Python/importlib.h
+++ b/Python/importlib.h
Binary files differ