Introduce snmp header file. It will be used in subsequent patch in
order to parse device statistics reported in
IFLA_INET6_STATS/IFLA_INET6_ICMP6STATS netlink attributes
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
