添加rtthread相关代码

riscv/rtthread/components/libc/posix/io/eventfd/eventfd.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2006-2023, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2023-07-20    zmq810150896  First version
+ */
+
+#ifndef __EVENTFD_H__
+#define __EVENTFD_H__
+
+int eventfd(unsigned int count, int flags);
+
+#endif /* __EVENTFD_H__ */