[PATCH nftables 0/4] socket: add support for "wildcard" key

[Balazs Scheidler <bazsi77@gmail.com>]

NOTE: this depends on a kernel patch, so please merge that before this can
be merged.  Also, apart from build testing and running the binaries on an
unpatched kernel (and confirming the netlink payload is formatted as it
should be) this is untested.

This series adds the nftables side of "socket wildcard" a new expression
that extracts whether the associated socket is bound to the ANY address or
not.

iptables originally had this behavior by default when using "-m socket
--transparent", but this was missing from nftables.


Also, the last patch in the series allows one to override the "nft"
executable used by the tests.