In prevision of following commits, supposed to add JSON output to the
tool, two files are copied from the iproute2 repository (taken at commit
268a9eee985f): lib/json_writer.c and include/json_writer.h.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>