Dependency to other apps and libraries
Currently, most distributions have GTK depending on a-i-t. I think going forward, @jimmac said that we want to remove this dependency since a-i-t is no longer some icon and cursor pack for everyone to use and apps should bundle their own icons.
With the new meson build system, we now make use of GTK for running gtk4-update-icon-cache. Right now we get a build error if GTK isn't installed.
I propose we make a-i-t dependent on GTK (a-i-t -> GTK)
Apps using a-i-t should make their own dependency if they need the icons, like Gaphor -> a-i-t (for use of symbolics in this case).