fix(lwip): Fixed compilation error referencing undefined POSIX interface API

Closes https://github.com/espressif/esp-idf/issues/13577

components/lwip/CMakeLists.txt

@@ -102,6 +102,10 @@ if(CONFIG_LWIP_ENABLE)
         "port/sockets_ext.c"
         "port/freertos/sys_arch.c")
 
+    if(CONFIG_LWIP_NETIF_API)
+        list(APPEND srcs "port/if_index.c")
+    endif()
+
     if(CONFIG_LWIP_PPP_SUPPORT)
         list(APPEND srcs
             "lwip/src/netif/ppp/auth.c"

components/lwip/port/if_index.c

@@ -0,0 +1,17 @@
+/*
+ * SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "lwip/if_api.h"
+
+unsigned int if_nametoindex(const char *ifname)
+{
+    return lwip_if_nametoindex(ifname);
+}
+
+char *if_indextoname(unsigned int ifindex, char *ifname)
+{
+    return lwip_if_indextoname(ifindex, ifname);
+}