Can't be built against tracker3 yet

https://github.com/mviereck/x11docker
Run GUI applications and desktops in docker. Focus on security.

streams support for PHP 7.4 and function definitions

ref #11937

A fix is available upstream: https://gitlab.gnome.org/GNOME/vala/-/issues/1068.
We can't just apply it though because it modifies the parts of Vala that
are written in Vala, so we'd have to rebootstrap the compiler. Since
a new release will be done soon for GNOME 3.38, we can just wait for that
and re-enable the tests when bumping.

due to failing unit tests