git://git.savannah.nongnu.org/lwip.git
4599f551dead9eac233b91c0b9ee5879f5d0620a

Upgrade procedure: Make sure to preserve the L4 changes in the lwIP source code.
They are clearly marked using "L4" in preprocessor conditions or comments. The
L4 changes currently consist of:

  - include/lwip/arch.h: LITTLE_ENDIAN/BIG_ENDIAN clash with uclibc
  - api/netdb.c, apps/ping/ping.c: Add missing LWIP_SOCKET_HAVE_SA_LEN checks
  - api/sockets.c: Allow sizeof(struct sockaddr_storage) (needed for uclibc)
  - contrib/ports/unix: Checks for L4Re
  - include/lwip/sockets.h, api/sockets.c: Support for system-wide select(),
    poll(), etc.
