message: Tell MSVC to always set a proper __cplusplus
diff: @@ -27,10 +27,10 @@ if (NOT MSVC)
  set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility-inlines-hidden")
  endif ()
  if (MSVC)
  - set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MT")
  - set (CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /MT")
  - set (CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL} /MT")
  - set (CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MTd")
  + set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MT /Zc:__cplusplus")
  + set (CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /MT /Zc:__cplusplus")
  + set (CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL} /MT /Zc:__cplusplus")
  + set (CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MTd /Zc:__cplusplus")
  set (CMAKE_C_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MT")
  set (CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /MT")
  set (CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL} /MT")
  