Sure, that should be no problem. The license requires that the code snippets you include keep their license and copyright attributions with them. I would suggest also including a link to the full version of the code (e.g. glib/gstring.c · main · GNOME / GLib · GitLab or a link which is pinned to a specific git revision).
Is there any way we can follow along and see how this paper progresses and is received? I’m interested. Thanks!