TBR: Fix build error in vdl tool.

Change-Id: I75d871384984076176da2a6889bd599c14c9c41f
diff --git a/cmd/vdl/make_builtin_vdlroot.go b/cmd/vdl/make_builtin_vdlroot.go
index 9ec3e5c..fffcf54 100644
--- a/cmd/vdl/make_builtin_vdlroot.go
+++ b/cmd/vdl/make_builtin_vdlroot.go
@@ -103,7 +103,7 @@
 	if jiriRoot == "" {
 		return fmt.Errorf("JIRI_ROOT is not set")
 	}
-	vdlroot := filepath.Join(v23root, "release", "go", "src", "v.io", "v23", "vdlroot")
+	vdlroot := filepath.Join(jiriRoot, "release", "go", "src", "v.io", "v23", "vdlroot")
 	wrapWriter := &wrapWriter{
 		writer:       out,
 		totalWritten: 0,