include/nuttx/net/ipv6ext.h: Fix some terminology: Hop-by-hop, not Hop-to-hop or Hop2hop.
net/devif/ipv6_input.c and net/icmpv6/icmpv6_input.c: Add logic to skiip over the variable number of IPv6 extension headers that may be present between the IPv6 header and the transport layer header. The extension headers are simply ignored. This is necessary because with MLD, certain incoming messages may have, at a mimimum, a Router Alert Hop-by-hop extension header.
net/inet/ipv6_setsockopt.c: Implement the IPV6_JOIN_GROUP and IPV6_LEAVE_GROUP socket options.
Squashed commit of the following:
sched: Rename all use of system_t to clock_t.
syscall: Rename all use of system_t to clock_t.
net: Rename all use of system_t to clock_t.
libs: Rename all use of system_t to clock_t.
fs: Rename all use of system_t to clock_t.
drivers: Rename all use of system_t to clock_t.
arch: Rename all use of system_t to clock_t.
include: Remove definition of systime_t; rename all use of system_t to clock_t.
Squashed commit of the following:
net/icmpv6: IPPROT_ICMP6 socket logic now builds without error.
net/icmpv6: Add support for read-ahead and poll(). Initial commit is just cloned from ICMP with the appropriate name changes.
configs/: All defconfig filess that include CONFIG_NET_ICMPv6_SOCKET=y need to select CONFIG_SYSTEM_PING6=y and deselect CONFIG_DISABLE_POLL.
Update NSH documention to show that ping6 is now a built in command.
net/icmpv6: Add icmpv6_sendto.c and icmpv6_recvfrom.c. Initial versions are just clones from icmp/ with appropriate name changes.
net/icmpv6: Clone some ICMP socket logic as the beginning of support for ICMPv6 socket support.
Rename CONFIG_NET_ICMPv6_PING to CONFIG_NET_ICMPv6_SOCKET. Move prototype for icmpv6_ping from include/nuttx/net/icmpv6 to net/icmpv6/icmpv6.h
