Fix build on Windows.

src/belle_sip_internal.h

@@ -1075,7 +1075,7 @@ void belle_sip_multipart_body_handler_progress_cb(belle_sip_body_handler_t *obj,
 belle_sip_list_t *belle_sip_parse_directory(const char *path, const char *file_type);
 
 typedef struct authorization_context authorization_context_t;
-void belle_sip_authorization_destroy(authorization_context_t* object);
+BELLESIP_EXPORT void belle_sip_authorization_destroy(authorization_context_t* object);
 
 
 #endif

tester/belle_sip_register_tester.c

@@ -944,7 +944,7 @@ void register_process_request_event(char *nonce, const belle_sip_request_event_t
 	belle_sip_server_transaction_send_response(trans,response_msg);
 }
 
-static void test_register_with_next_nonce() {
+static void test_register_with_next_nonce(void) {
 	belle_sip_listening_point_t *server_lp = belle_sip_stack_create_listening_point(stack,"0.0.0.0",bctbx_random()%20000 +1024,"TCP");
 	char  nonce [NONCE_SIZE];
 	belle_sip_listener_t *server_listener;