build-sys: libudev - get rid of the needless selinux linking (again)
libudev: Move -lrt to Libs.private It's only needed for static linking. https://bugs.freedesktop.org/show_bug.cgi?id=63309
libudev: update copyright headers
udev: move libudev, gudev to src/; move gudev/docs/, udev/docs/ to to docs/