Follow symlinks when using the tarball exporting feature
Submitted by Jeff F.T.
To save space, I sometimes use soft symbolic links (you can create them with Nautilus, or using "ln -s") to avoid duplicating files
When creating the xges_tar tarball for export, we don't actually follow the links, so they end up getting packaged as (broken) links.
Instead the code should check if the link is still valid, and if so use its target (and rename it into the tarball to match the link's name).
Imported from https://bugzilla.gnome.org/show_bug.cgi?id=740551