diff --git a/graphics/opencv/patches/patch-modules_dnn_test__precomp.hpp b/graphics/opencv/patches/patch-modules_dnn_test__precomp.hpp
new file mode 100644
index 000000000000..767be0c2ef31
--- /dev/null
+++ b/graphics/opencv/patches/patch-modules_dnn_test__precomp.hpp
@@ -0,0 +1,20 @@
+$NetBSD: patch-modules_dnn_test__precomp.hpp,v 1.1 2019/04/29 03:23:53 mef Exp $
+
+adhoc patch to build 3.4.6
+
+[ 30%] Built target opencv_core
+/export/WRKOBJDIR/graphics/opencv/work/opencv-3.4.6/build/modules/dnn/test_precomp.hpp:50:10: fatal error: test/test_common.hpp: No such file or directory
+ #include "test/test_common.hpp"
+          ^~~~~~~~~~~~~~~~~~~~~~
+compilation terminated.
+
+--- build/modules/dnn/test_precomp.hpp.orig	2019-04-29 10:35:50.011315095 +0900
++++ modules/dnn/test/test_precomp.hpp	2019-04-29 11:11:41.277591395 +0900
+@@ -47,6 +47,6 @@
+ #include "opencv2/core/ocl.hpp"
+ 
+ #include "opencv2/dnn.hpp"
+-#include "test_common.hpp"
++#include "../test/test_common.hpp"
+ 
+ #endif