message: Export symbols when building dll
diff: @@ -5,7 +5,8 @@ cmake_minimum_required (VERSION 3.12)
  project (azure-storage LANGUAGES CXX)
  set(CMAKE_CXX_STANDARD 14)
  -set(CMAKE_CXX_STANDARD_REQUIRED True)
  +set(CMAKE_CXX_STANDARD_REQUIRED ON)
  +set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
  option(BUILD_STORAGE_SAMPLES "Build sample codes" ON)
  