--- /dev/null
+#ifndef __SYS_LOCK_H__
+#define __SYS_LOCK_H__
+
+/* dummy lock routines for single-threaded aps */
+
+typedef int _LOCK_T;
+typedef int _LOCK_RECURSIVE_T;
+
+#include <_ansi.h>
+
+#define __LOCK_INIT(class,lock) static int lock = 0;
+#define __LOCK_INIT_RECURSIVE(class,lock) static int lock = 0;
+#define __lock_init(lock) (_CAST_VOID 0)
+#define __lock_init_recursive(lock) (_CAST_VOID 0)
+#define __lock_close(lock) (_CAST_VOID 0)
+#define __lock_close_recursive(lock) (_CAST_VOID 0)
+#define __lock_acquire(lock) (_CAST_VOID 0)
+#define __lock_acquire_recursive(lock) (_CAST_VOID 0)
+#define __lock_try_acquire(lock) (_CAST_VOID 0)
+#define __lock_try_acquire_recursive(lock) (_CAST_VOID 0)
+#define __lock_release(lock) (_CAST_VOID 0)
+#define __lock_release_recursive(lock) (_CAST_VOID 0)
+
+#endif /* __SYS_LOCK_H__ */