glib 2.75.3 changes warning behaviour of `g_string_free()`. See: * https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3219 * https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3226 Use this opportunity to replace the use of GString with `g_strdup_printf()` where possible. Otherwise correctly take the return value of `g_string_free()` which is nicer anyways.