MDEV-35632: HandlerSocket uses deprecated auto_ptr

Let us suppress the deprecation warnings more specifically.

This fixes up commit d76f5774fe

plugin/handler_socket/libhsclient/hstcpcli.hpp

@@ -19,6 +19,11 @@
 #include "string_ref.hpp"
 #include "string_buffer.hpp"
 
+#ifdef __GNUC__
+/* auto_ptr is deprecated */
+# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
+
 namespace dena {
 
 struct hstcpcli_filter {