Allow configuration of local netif hostname via new LWIP component configuration menu item

Signed-off-by: Sagar Bijwe <sagar@espressif.com>

Merges https://github.com/espressif/esp-idf/pull/3627

components/lwip/Kconfig

@@ -1,5 +1,11 @@
 menu "LWIP"
 
+    config LWIP_LOCAL_HOSTNAME
+        string "Local netif hostname"
+        default 'espressif'
+        help
+            The name this device will report to other devices on the network
+
     config LWIP_L2_TO_L3_COPY
         bool "Enable copy between Layer2 and Layer3 packets"
         default n

components/lwip/port/esp32/netif/ethernetif.c

@@ -222,7 +222,7 @@ ethernetif_init(struct netif *netif)
   /* Initialize interface hostname */
 
 #if ESP_LWIP
-  netif->hostname = "espressif";
+  netif->hostname = CONFIG_LWIP_LOCAL_HOSTNAME;
 #else
   netif->hostname = "lwip";
 #endif

components/lwip/port/esp32/netif/nettestif.c

@@ -39,7 +39,7 @@ err_t nettestif_init(struct netif *netif)
 
   g_last_netif = netif;
 
-  netif->hostname = "espressif";
+  netif->hostname = CONFIG_LWIP_LOCAL_HOSTNAME;
 
   /*
    * Initialize the snmp variables and counters inside the struct netif.

components/lwip/port/esp32/netif/wlanif.c

@@ -202,7 +202,7 @@ wlanif_init(struct netif *netif)
   /* Initialize interface hostname */
 
 #if ESP_LWIP
-  netif->hostname = "espressif";
+  netif->hostname = CONFIG_LWIP_LOCAL_HOSTNAME;
 #else
   netif->hostname = "lwip";
 #endif