get mqtt_client building

lwipopts.h

@@ -1,10 +1,33 @@
 #ifndef _LWIPOPTS_H
 #define _LWIPOPTS_H
 
+// Need more memory for TLS
+#ifdef MQTT_CERT_INC
+#define MEM_SIZE 8000
+#endif
+
 // Generally you would define your own explicit list of lwIP options
 // (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html)
 //
 // This example uses a common include to avoid repetition
 #include "lwipopts_examples_common.h"
 
-#endif
+#define MEMP_NUM_SYS_TIMEOUT        (LWIP_NUM_SYS_TIMEOUT_INTERNAL+1)
+
+#ifdef MQTT_CERT_INC
+#define LWIP_ALTCP               1
+#define LWIP_ALTCP_TLS           1
+#define LWIP_ALTCP_TLS_MBEDTLS   1
+#ifndef NDEBUG
+#define ALTCP_MBEDTLS_DEBUG  LWIP_DBG_ON
+#endif
+/* TCP WND must be at least 16 kb to match TLS record size
+   or you will get a warning "altcp_tls: TCP_WND is smaller than the RX decrypion buffer, connection RX might stall!" */
+#undef TCP_WND
+#define TCP_WND  16384
+#endif // MQTT_CERT_INC
+
+// This defaults to 4
+#define MQTT_REQ_MAX_IN_FLIGHT 5
+
+#endif