Merge branch 'bpftool-add-a-version-command-and-fix-several-items'

Jakub Kicinski says:

====================
tools: bpftool: add a "version" command, and fix several items

Quentin says:

The first seven patches of this series bring several minor fixes to
bpftool. Please see individual commit logs for details.

Last patch adds a "version" commands to bpftool, which is in fact the
version of the kernel from which it was compiled.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>