Function add

bitcoin/psbt.c:465–470

}

static void add(u8 **key, const void *mem, size_t len)
{
	size_t oldlen = tal_count(*key);
	tal_resize(key, oldlen + len);
	memcpy(*key + oldlen, memcheck(mem, len), len);
}

static void add_type(u8 **key, const u8 num)
{