I understand that updated headers are needed in order for the new
version of VLC to compile successfully. Please see attached. I hope
this is sufficient.

Also, since Alexandre Oliva periodically removes tarballs so as to
free up space on the virtual machine that hosts these, it might also
be a good idea to put a copy of linux-libre-3.18.11-gnu.tar.xz in
http://alpha.gnu.org/gnu/guix/mirror/ along with the current version
3.3.8.