When using the statement expression and a stack object along with
clang-11 and libasan, we get quite a lot of errors about reading
invalid memory. This is due to clang making the actual listener_t local
to the block, such that the access outside of the macros using
_assert_payload is (correctly) considered an error.
By using a heap allocated object, we can destroy it once the listener
returns FALSE (cleaning up properly), and since bus_t does not touch the
listener after that, we don't get any errors from libasan.
Co-authored-by: Tobias Brunner <tobias@strongswan.org>
