Apparently, VC++ compiler does not accept -Wextra option

CMakeLists.txt

@@ -44,12 +44,12 @@ if (ELFIO_BUILD_EXAMPLES OR ELFIO_BUILD_TESTS)
 endif()
 
 if (ELFIO_BUILD_EXAMPLES)
-    set (CMAKE_CXX_FLAGS "-Wall -Wextra")
+    # set (CMAKE_CXX_FLAGS "-Wall")
     add_subdirectory(examples)
 endif()
 
 if (ELFIO_BUILD_TESTS AND IS_TOP_PROJECT)
-    set (CMAKE_CXX_FLAGS "-Wall -Wextra")
+    # set (CMAKE_CXX_FLAGS "-Wall")
     enable_testing()
     add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} USES_TERMINAL)
     add_subdirectory(tests)