v4.19.13 snapshot.
diff --git a/tools/testing/radix-tree/linux/init.h b/tools/testing/radix-tree/linux/init.h
new file mode 100644
index 0000000..1bb0afc
--- /dev/null
+++ b/tools/testing/radix-tree/linux/init.h
@@ -0,0 +1 @@
+#define __init