be compatible with `log4cxx` `0.11` and `0.12`/`0.13` [`log4cxx` uses `std::shared_ptr`](https://issues.apache.org/jira/browse/LOGCXX-486) since [version `0.12`](https://logging.apache.org/log4cxx/latest_stable/changelog.html)
Unfortunately Ubuntu 22.04 ships with [`0.12`](https://packages.ubuntu.com/jammy/liblog4cxx12), which means that rosconsole with the `log4cxx` backend wouldn't compile. This is also a problem on other distros such as Arch or Gentoo.
I have carefully applied explicit construction/conversion and `&*` instead of `.get()` to make the code compile with both versions of `log4cxx`.
Daniel Reuter <daniel.robin.reuter@googlemail.com>
