Fixed some function definitions.

Future releases of GCC will render function definitions like

  func()

invalid by default. See the previous commit 09f88c9 ("Fixed main()
prototypes in auto tests.") for details.

Such functions should be defined like

  func(void)

This is a good thing to do regardless of the upcoming GCC changes.

Reviewed-by: Alejandro Colomar <alx@nginx.com>
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

src/test/nxt_unit_websocket_chat.c

@@ -201,7 +201,7 @@ ws_chat_close_handler(nxt_unit_request_info_t *req)
 
 
 int
-main()
+main(void)
 {
     nxt_unit_ctx_t   *ctx;
     nxt_unit_init_t  init;

src/test/nxt_unit_websocket_echo.c

@@ -83,7 +83,7 @@ ws_echo_websocket_handler(nxt_unit_websocket_frame_t *ws)
 
 
 int
-main()
+main(void)
 {
     nxt_unit_ctx_t   *ctx;
     nxt_unit_init_t  init;