libubox: update to Git HEAD (2026-02-13)

libubox: update to Git HEAD (2026-02-13)

d324c0503040 libubox: send warnings to stderr
5a65cb5a79b7 libubox: document positional arguments
8c7b489daa02 libubox: add anonymous strings, ints, et al in arrays
5ec7ff2effb3 uloop: use volatile sig_atomic_t for do_sigchld flag
0efa2cd3b74c usock: check SO_ERROR after poll in usock_inet_timeout()
1a73ded9f738 usock: fix timeout handling in usock_inet_timeout()
1aa36ee774c8 usock: implement RFC 8305 Happy Eyeballs for usock_inet_timeout()

Fixes: https://github.com/openwrt/uclient/issues/8
Signed-off-by: Felix Fietkau <nbd@nbd.name>