build: Do not install generated GLib GIR files
GLib 2.79 ships its own introspection data.
We need to keep generating the introspection data for GIRepository-2.0, but we don't need to install its dependencies.
GLib 2.79 ships its own introspection data.
We need to keep generating the introspection data for GIRepository-2.0, but we don't need to install its dependencies.