include C++ extensions based on _MSVC_LANG

Author: Marcin Sobieszczanski

hdr/sqlite_modern_cpp/type_wrapper.h

@@ -5,20 +5,20 @@
 #include <memory>
 #include <vector>
 #ifdef __has_include
-#if __cplusplus >= 201703 && __has_include(<string_view>)
+#if (__cplusplus >= 201703 || _MSVC_LANG >= 201703) && __has_include(<string_view>)
 #define MODERN_SQLITE_STRINGVIEW_SUPPORT
 #endif
 #endif
 #ifdef __has_include
-#if __cplusplus > 201402 && __has_include(<optional>)
+#if (__cplusplus > 201402 || _MSCV_LANG > 201402) && __has_include(<optional>)
 #define MODERN_SQLITE_STD_OPTIONAL_SUPPORT
 #elif __has_include(<experimental/optional>) && __apple_build_version__ < 11000000
 #define MODERN_SQLITE_EXPERIMENTAL_OPTIONAL_SUPPORT
 #endif
 #endif
 
 #ifdef __has_include
-#if __cplusplus > 201402 && __has_include(<variant>)
+#if (__cplusplus > 201402 || _MSVC_LANG > 201402) && __has_include(<variant>)
 #define MODERN_SQLITE_STD_VARIANT_SUPPORT
 #endif
 #endif