esp_netif/tcpip_adapter: declare functions extern "C"

Merges https://github.com/espressif/esp-idf/pull/4408

components/tcpip_adapter/include/tcpip_adapter.h

@@ -23,6 +23,10 @@
 
 #include "tcpip_adapter_types.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * @brief tcpip adapter legacy init. It is used only to set the compatibility mode of esp-netif, which
  * will enable backward compatibility of esp-netif.
@@ -245,4 +249,8 @@ esp_err_t tcpip_adapter_get_hostname(tcpip_adapter_if_t tcpip_if, const char **h
  */
 esp_err_t tcpip_adapter_set_default_wifi_handlers(void);
 
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 #endif //_TCPIP_ADAPTER_H_

components/tcpip_adapter/include/tcpip_adapter_compatible/tcpip_adapter_compat.h

@@ -15,6 +15,10 @@
 #ifndef _TCPIP_ADAPTER_COMPAT_H_
 #define _TCPIP_ADAPTER_COMPAT_H_
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  * @brief This function is called from ethernet driver init code to facilitate
  * autostart fo the driver in backward compatible tcpip_adapter way
@@ -54,4 +58,8 @@ esp_err_t tcpip_adapter_set_default_wifi_handlers(void);
  */
 esp_err_t tcpip_adapter_clear_default_wifi_handlers(void);
 
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 #endif //_TCPIP_ADAPTER_COMPAT_H_

components/tcpip_adapter/include/tcpip_adapter_types.h

@@ -18,6 +18,11 @@
 #include "lwip/ip_addr.h"
 #include "dhcpserver/dhcpserver.h"
 #include "esp_netif_sta_list.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 //
 // Define compatible types if tcpip_adapter interface used
 //
@@ -70,4 +75,8 @@ typedef esp_netif_dns_info_t tcpip_adapter_dns_info_t;
 typedef esp_netif_sta_list_t tcpip_adapter_sta_list_t;
 typedef esp_netif_sta_info_t tcpip_adapter_sta_info_t;
 
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 #endif // _TCPIP_ADAPTER_TYPES_H_