diff --git a/3rdparty/include/opencl/1.2/CL/cl_platform.h b/3rdparty/include/opencl/1.2/CL/cl_platform.h
index cf2b7210ac..46b3d9dcdc 100644
--- a/3rdparty/include/opencl/1.2/CL/cl_platform.h
+++ b/3rdparty/include/opencl/1.2/CL/cl_platform.h
@@ -92,7 +92,7 @@ extern "C" {
             #define CL_EXT_SUFFIX__VERSION_1_1_DEPRECATED __attribute__((deprecated))
             #define CL_EXT_PREFIX__VERSION_1_1_DEPRECATED    
         #endif
-    #elif _WIN32
+    #elif defined(_WIN32)
         #ifdef CL_USE_DEPRECATED_OPENCL_1_0_APIS
             #define CL_EXT_SUFFIX__VERSION_1_0_DEPRECATED    
             #define CL_EXT_PREFIX__VERSION_1_0_DEPRECATED    
diff --git a/modules/ocl/CMakeLists.txt b/modules/ocl/CMakeLists.txt
index a35aea0e2d..21e0b30858 100644
--- a/modules/ocl/CMakeLists.txt
+++ b/modules/ocl/CMakeLists.txt
@@ -5,4 +5,4 @@ endif()
 
 set(the_description "OpenCL-accelerated Computer Vision")
 ocv_define_module(ocl opencv_core opencv_imgproc opencv_features2d opencv_objdetect opencv_video opencv_calib3d opencv_ml "${OPENCL_LIBRARIES}")
-ocv_warnings_disable(CMAKE_CXX_FLAGS -Wshadow -Wundef)
+ocv_warnings_disable(CMAKE_CXX_FLAGS -Wshadow)