eliminate build warnings

modules/calib3d/src/chessboard.cpp

@@ -797,15 +797,6 @@ Ellipse::Ellipse(const cv::Point2f &_center, const cv::Size2f &_axes, float _ang
 {
 }
 
-Ellipse::Ellipse(const Ellipse &other)
-{
-    center = other.center;
-    axes= other.axes;
-    angle= other.angle;
-    cosf = other.cosf;
-    sinf = other.sinf;
-}
-
 const cv::Size2f &Ellipse::getAxes()const
 {
     return axes;

modules/calib3d/src/chessboard.hpp

@@ -111,8 +111,6 @@ class Ellipse
     public:
         Ellipse();
         Ellipse(const cv::Point2f &center, const cv::Size2f &axes, float angle);
-        Ellipse(const Ellipse &other);
-
 
         void draw(cv::InputOutputArray img,const cv::Scalar &color = cv::Scalar::all(120))const;
         bool contains(const cv::Point2f &pt)const;

modules/core/src/parallel.cpp

@@ -95,6 +95,9 @@
 */
 
 #if defined HAVE_TBB
+    #ifndef TBB_SUPPRESS_DEPRECATED_MESSAGES  // supress warning
+    #define TBB_SUPPRESS_DEPRECATED_MESSAGES 1
+    #endif
     #include "tbb/tbb.h"
     #include "tbb/task.h"
     #include "tbb/tbb_stddef.h"

modules/dnn/CMakeLists.txt

@@ -122,6 +122,7 @@ endif()
 ocv_module_include_directories(${include_dirs})
 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   ocv_append_source_files_cxx_compiler_options(fw_srcs "-Wno-suggest-override")  # GCC
+  ocv_append_source_files_cxx_compiler_options(fw_srcs "-Wno-array-bounds")  # GCC 9.3.0 (Ubuntu 20.04)
 elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
   ocv_append_source_files_cxx_compiler_options(fw_srcs "-Wno-inconsistent-missing-override")  # Clang
 endif()