wifi-headerfile-updates

1, add "extern "C" {}  " to "wifi_ind.h" for being called by CPP files.

targets/TARGET_Realtek/TARGET_AMEBA/sdk/common/api/wifi/wifi_ind.h

@@ -32,6 +32,10 @@
  
 #include "wifi_conf.h"  
 
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
 typedef void (*rtw_event_handler_t)(char *buf, int buf_len, int flags, void* handler_user_data );
 
 typedef struct
@@ -90,6 +94,10 @@ extern void wifi_reg_event_handler(unsigned int event_cmds, rtw_event_handler_t
  */
 extern void wifi_unreg_event_handler(unsigned int event_cmds, rtw_event_handler_t handler_func);
 
+#ifdef __cplusplus
+  }
+#endif
+
 /*\@}*/
 
 #endif //_WIFI_INDICATE_H