New code from lwip project

lwip repo:
8558fa0 etharp_entry::ctime must be u16_t after changing ARP_TMR_INTERVAL from 5 seconds to 1 second when fixing bug #34682
f36d6b7 fixed bug #39514 ip_route() may return an IPv6-only interface
e990804 fixed bug #39356 Wrong increment in pbuf_memfind()
dceed2e fixed bug #39225 udp.c uses netif_matches_ip6_addr() incorrectly; renamed function netif_matches_ip6_addr() to netif_get_ip6_addr_match()
7b63878 Fixed bug #39224 Unused IPv6 address state defines in nd6
01ecd35 fixed bug #39145 IGMP membership report for 224.0.0.1 -> ensure that we never send a report for 224.0.0.1
fbdea8d fixed bug #39076 ETHARP_STATS is not defined when LWIP_STATS is 0
07fbe82 fixed bug #34681 Limit ARP queue length by ARP_QUEUE_LEN (=3)
05a9675 fixed bug #34682 Limit ARP request flood for unresolved entry
fc158ad Fixed netconn_gethostbyname for LWIP_MPU_COMPATIBLE: removed invalid check on 'addr', copy 'name' since it could be located on the caller's stack
4d69d0e Fixed IPv6 raw checksumming after a hint from Philip Gladstone
2225b8a fixed bug #39683 Assertion "seg->tcphdr not aligned" failed with MEM_ALIGNMENT = 8
9572db2 Fixed bug #39718: disconnecting an UDP socket reports an error
515e4b9 fixed bug #39882 No function shall set errno to 0
c1dc1a2 fixed bug #40050 SNMP problem with MIB arrays > 255
a58083b Fixed comment on LWIP_HAVE_LOOPIF
0f24fba IGMP: fixed !define LWIP_RAND case
4d774e2 netconn::recv_avail: forgot one line
a2d6a50 fixed bug #41499 netconn::recv_avail can overflow
08b56e8 SNMP: mib-2.system.sysObjectID is read-only, so make the object "static const" and modify just the pointer; snmp_get_sysobjid_ptr() and snmp_set_sysobjid() take a pointer to "const" object now
7a77917 SNMP: use MEMCPY() instead of ocstrncpy() and objectidncpy()
e432014 netif: Update header file documentation
a89db98 Added missing IPPROTO_RAW
6dcc85d patch #7993: Added support for transmitting packets with VLAN headers via hook function LWIP_HOOK_VLAN_SET and to check them via hook function LWIP_HOOK_VLAN_CHECK
a375ea4 Minor: coding style cleanups...
d74464e Add RFC3542-style checksum compuation on raw, IPv6 sockets
e2c2afb patch #7885: modification of api modules to support FreeRTOS-MPU (don't pass stack-pointers to other threads) (based on patch by Artem Pisarenko)
cffe54d Patch #7815 by James Smith: added inet_ntop/inet_pton
2f02120 Fixed typo.

lwip-contrib repo:
856e9ec Fixed compiler warnings (unused variables)
c2539db Fixed bug #39380 Cannot build smtp example when debug is disabled
bb3e70c Fixed bug #41498 simhost unix project in lwip-contrib calls netif_init() twice.
21e076c patch #8097 httpd: Return failure if parsing Content-Length fails