Also fixed a typo in the library (but I guess that code isn't executed, otherwise we should have noticed in the last 10 years (since https://github.com/piwik/piwik/commit/e8700c0c7dd08869b93ed1d092d90bb7cd3716e3))
I also don’t have a running php 7.2 system, so I haven’t tested it.
And travis doesn’t seem to like me, as it either runs for 6 hours or fails at Cloning into 'submodules/browser-logos'... (a submodule of my piwik icons repo)
Maybe we shouldn’t clone submodules recursively.
Seems travis had some problems or so. I've restarted the builds and now it succeeded.