I have an error compiling dns.c because of LWIP_RAND function is not defined.
I've checked git log and looks like this function is optional.
Is there any reason why it necessarily has to be used in dns.c?
dns.c listing from line 88:
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/* A list of DNS security features follows */
#define LWIP_DNS_SECURE_RAND_XID 1
#define LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING 2
#define LWIP_DNS_SECURE_RAND_SRC_PORT 4
/** Use all DNS security features by default.
* This is overridable but should only be needed by very small targets
* or when using against non standard DNS servers. */
#ifndef LWIP_DNS_SECURE
#define LWIP_DNS_SECURE (LWIP_DNS_SECURE_RAND_XID | LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING | LWIP_DNS_SECURE_RAND_SRC_PORT)
#endif
/** Random generator function to create random TXIDs and source ports for queries */
#ifndef DNS_RAND_TXID
#if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_XID) != 0)
#define DNS_RAND_TXID LWIP_RAND
#else
static u16_t dns_txid;
#define DNS_RAND_TXID() (++dns_txid)
#endif
#endif
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Regards,
Gennady