ref: 5ebb1a29d8250027e8b7f2287f3bfa3a6f3d13ac dir: /sys/src/ape/lib/bsd/in6_addr.c/
#include <netinet/in.h> struct in6_addr in6addr_any = IN6ADDR_ANY_INIT; struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;