glib now warns if the return value is not used, so use the API as intended instead of assigning the character data separately before freeing the GString. Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2625>
This is all of the original libcroco, minus these two which we don't use: - cr-sel-eng - the CSS selection engine for xmlNode. - cr-style. Part of https://gitlab.gnome.org/GNOME/gnome-shell/issues/1934