net: ipv6 support, merge unix+ip;[pack:x] attribute (#9904)

vlib/net/address_default.c.v

@@ -0,0 +1,32 @@
+module net
+
+const max_unix_path = 104
+
+struct C.addrinfo {
+mut:
+	ai_family    int
+	ai_socktype  int
+	ai_flags     int
+	ai_protocol  int
+	ai_addrlen   int
+	ai_addr      voidptr
+	ai_canonname voidptr
+	ai_next      voidptr
+}
+
+struct C.sockaddr_in {
+	sin_family byte
+	sin_port   u16
+	sin_addr   u32
+}
+
+struct C.sockaddr_in6 {
+	sin6_family byte
+	sin6_port   u16
+	sin6_addr   [4]u32
+}
+
+struct C.sockaddr_un {
+	sun_family byte
+	sun_path   [max_unix_path]char
+}