lwip: Changed to C linkage for fixing bug when using mixed C/C++ code

Merges https://github.com/espressif/esp-idf/pull/5900

components/lwip/port/esp32/include/netdb.h

@@ -32,9 +32,17 @@
 
 #include "lwip/netdb.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+  
 #ifdef ESP_PLATFORM
 int getnameinfo(const struct sockaddr *addr, socklen_t addrlen,
                 char *host, socklen_t hostlen,
                 char *serv, socklen_t servlen, int flags);
 
 #endif
+
+#ifdef __cplusplus
+}
+#endif