SDK Regression : clutter-gtk does not work on X11 with master SDK

Reproduction: Run org.gnome.Maps nightly on a X11 desktop (Tried: Ubuntu 16.04 and Fedora 29). This fails with "Unsupported back-end" error in journal. Using a stable maps build with 3.30 SDK works fine on X11. maps nightly works fine on Wayland session.