Enable QT_FEATURE_zstd
As reported in
- https://github.com/flathub/org.kde.WaylandDecoration.QGnomePlatform-decoration/issues/4
- https://aur.archlinux.org/packages/qt6-base-headless#comment-870128
- https://github.com/flathub/com.calibre_ebook.calibre/issues/34#issuecomment-1433253994
missing this feature will cause applications to fail to initialize properly. In particular, those applications that can't be rebuilt in the flatpak environment.
Edited by Helen Simons