message: Enable Clang warning "-Wshadow"
diff: @@ -396,6 +396,10 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  list(APPEND warning_flags -Wcomma)
  endif()
  + if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9.0)
  + list(APPEND warning_flags -Wshadow)
  + endif()
  +
  if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0 AND NOT APPLE)
  list(APPEND warning_flags -Wno-unused-lambda-capture)
  endif()
  