Merge pull request #16237 from alalek:eliminate_build_warnings

cmake/OpenCVUtils.cmake

@@ -401,7 +401,7 @@ macro(ocv_clear_vars)
 endmacro()
 
 set(OCV_COMPILER_FAIL_REGEX
-    "argument '.*' is not valid"                # GCC 9+
+    "argument .* is not valid"                  # GCC 9+ (including support of unicode quotes)
     "command line option .* is valid for .* but not for C\\+\\+" # GNU
     "command line option .* is valid for .* but not for C" # GNU
     "unrecognized .*option"                     # GNU

samples/opencl/opencl-opencv-interop.cpp

@@ -17,6 +17,7 @@
 #define CL_USE_DEPRECATED_OPENCL_1_1_APIS
 #define CL_USE_DEPRECATED_OPENCL_1_2_APIS
 #define CL_USE_DEPRECATED_OPENCL_2_0_APIS // eliminate build warning
+#define CL_TARGET_OPENCL_VERSION 200  // 2.0
 
 #ifdef __APPLE__
 #define CL_SILENCE_DEPRECATION
@@ -677,7 +678,7 @@ int App::initVideoSource()
             throw std::runtime_error(std::string("specify video source"));
     }
 
-    catch (const std::exception e)
+    catch (const std::exception& e)
     {
         cerr << "ERROR: " << e.what() << std::endl;
         return -1;