add new socket options SO_INCOMING_CPU, SO_ATTACH_BPF, SO_DETACH_BPF

add new socket options SO_INCOMING_CPU, SO_ATTACH_BPF, SO_DETACH_BPF

these socket options are new in linux v3.19, introduced in commit
2c8c56e15df3d4c2af3d656e44feb18789f75837 and commit
89aa075832b0da4402acebd698d0411dcc82d03e

with SO_INCOMING_CPU the cpu can be queried on which a socket is
managed inside the kernel and optimize polling of large number of
sockets accordingly.

SO_ATTACH_BPF lets eBPF programs (created by the bpf syscall) to
be attached to sockets.