Again I missed the 14 day response time by a few hours
I just tried what you suggested as
meson --prefix /opt/gtk builddir ninja -C builddir ninja -C builddir install
So I did
rm -rf /opt/gtk rm -rf gtk git clone https://gitlab.gnome.org/GNOME/gtk.git cd gtk meson --prefix /opt/gtk builddir
But that results in
meson.build:358:2: ERROR: Inconsistency: Subproject has overriden the dependency with another variable than 'libpangoft2_dep'
So that recipe is too simple. I have no idea what the concrete problem is, but I think I have to fall back to my initial solution, hope that that one will still work.