IDF release/v3.3 (#3672)

ESP-IDF release/v3.3: 66d3783c8
esp-face: 420fc7e
esp32-camera: 0107093

tools/sdk/include/lwip/netif/ppp/pppos.h

@@ -42,6 +42,10 @@
 #include "ppp.h"
 #include "vj.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* PPP packet parser states.  Current state indicates operation yet to be
  * completed. */
 enum {
@@ -114,5 +118,9 @@ void pppos_input(ppp_pcb *ppp, u8_t* data, int len);
 err_t pppos_input_sys(struct pbuf *p, struct netif *inp);
 #endif /* !NO_SYS && !PPP_INPROC_IRQ_SAFE */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* PPPOS_H */
 #endif /* PPP_SUPPORT && PPPOL2TP_SUPPORT */