OpenGL interop sample reworked not ot use cvconfig.h

samples/gpu/CMakeLists.txt

@@ -71,6 +71,10 @@ if(BUILD_EXAMPLES AND OCV_DEPENDENCIES_FOUND)
 
   file(GLOB all_samples RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.cpp)
 
+  if(NOT WITH_OPENGL)
+    list(REMOVE_ITEM all_samples "opengl.cpp")
+  endif(NOT WITH_OPENGL)
+
   foreach(sample_filename ${all_samples})
     get_filename_component(sample ${sample_filename} NAME_WE)
     file(GLOB sample_srcs RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ${sample}.*)
@@ -82,6 +86,9 @@ endif()
 
 if (OCV_DEPENDENCIES_FOUND AND INSTALL_C_EXAMPLES AND NOT WIN32)
   file(GLOB install_list *.c *.cpp *.jpg *.png *.data makefile.* build_all.sh *.dsp *.cmd )
+  if(NOT WITH_OPENGL)
+    list(REMOVE_ITEM all_samples "opengl.cpp")
+  endif(NOT WITH_OPENGL)
   install(FILES ${install_list}
           DESTINATION ${OPENCV_SAMPLES_SRC_INSTALL_PATH}/gpu
           PERMISSIONS OWNER_READ GROUP_READ WORLD_READ COMPONENT samples)

samples/gpu/opengl.cpp

 #include <iostream>
-#include "cvconfig.h"
-
-#ifndef HAVE_OPENGL
-int main()
-{
-    std::cerr << "Library was built without OpenGL support" << std::endl;
-    return -1;
-}
-#else
 
 #ifdef WIN32
     #define WIN32_LEAN_AND_MEAN 1