lsof: convert to gentargets and bump to 4.84

lsof is packaged as a tarball inside a .tar.bz2 package, so we have a
post-extract hook to extract the source code tarball, so that for the
next steps, lsof looks like a normal package.

Signed-off-by: Martin Banky <Martin.Banky@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>