Compatibiliity with Gentoo (AppImage)

See https://github.com/synfig/synfig/issues/3628

```
sudo emerge --sync
sudo emerge audit
sudo ln -s /usr/lib64/libaudit.so.1   /usr/lib64/libselinux.so.1
sudo ln -s /usr/lib64/libelogind.so.0 /usr/lib64/libsystemd.so.0
```