Use _MSVC_LANG macro

Author: vstinner

Include/pyport.h

@@ -540,10 +540,15 @@ extern "C" {
 //
 // On C23, use typeof(). On C++11, use decltype(). Otherwise, use __typeof__()
 // if on GCC, clang or MSVC 17.9 and newer.
+//
+// On MSVC, check also _MSVC_LANG since __cplusplus is 199711L unless
+// the /Zc:__cplusplus flag is used.
 #if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
 #  define _Py_TYPEOF(expr) typeof(expr)
 #elif defined(__cplusplus) && __cplusplus >= 201103L
 #  define _Py_TYPEOF(expr) decltype(expr)
+#elif defined(_MSVC_LANG) && _MSVC_LANG >= 201103L
+#  define _Py_TYPEOF(expr) decltype(expr)
 #elif defined(__GNUC__) || defined(__clang__) || \
     (defined(_MSC_VER) && _MSC_VER >= 1939)
 #  define _Py_TYPEOF(expr) __typeof__(expr)