This installs the headers in a fashion which matches Gentoo, and it also
changes the version numbering scheme as well to match, so hopefully
Nixpkgs Monitor can provide security tracking updates or anything
(although technically Gentoo is outdated!)
[Bjørn: add github pull-request cover letter to commit message; it
contains useful info.]
Signed-off-by: Austin Seipp <aseipp@pobox.com>
