jammy: enable GTK4 build for webkit2gtk

[Jeremy Bícha]

When you update Ubuntu 22.04 LTS with webkit2gtk 2.40, please consider enabling the GTK4 build (webkitgtk-6.0).

This would be useful for snapping GTK4 apps that use webkit. The most prominent example is epiphany.

On the other hand, enabling the GTK4 build will lengthen the build time. The Ubuntu 22.04 LTS webkit2gtk package is building itself twice, once for 4.0 (gtk3 + libsoup2) and once for 4.1 (gtk3+ libsoup3). This request is for a third build: 6.0 (gtk4 + libsoup3).

I'm marking as Security since the Security Team does most of the webkit2gtk uploads for Ubuntu stable releases.

[Heather Ellsworth (hellsworth)]

It sounds like this was done already, so the issue should be closed:

https://github.com/ubuntu/epiphany/issues/6#issuecomment-1666190061

Jeremy, please confirm.