macros: fix support of Windows compilers

src/macros.hpp

 //
-// Copyright (c) 2017-2019 CNRS INRIA
+// Copyright (c) 2017-2020 CNRS INRIA
 //
 
 #ifndef __pinocchio_macros_hpp__
 #define __pinocchio_macros_hpp__
 
-#if __cplusplus >= 201103L
-  #define PINOCCHIO_WITH_CXX11_SUPPORT
+// On Windows, __cplusplus is not necessarily set to the C++ version being used.
+// See https://docs.microsoft.com/fr-fr/cpp/build/reference/zc-cplusplus?view=vs-2019 for further information.
+
+#if __cplusplus >= 201703L
+  #define PINOCCHIO_WITH_CXX17_SUPPORT
+#elif defined(_MSVC_LANG)
+  #if _MSVC_LANG >= 201703L
+    #define PINOCCHIO_WITH_CXX17_SUPPORT
+  #endif
 #endif
 
 #if __cplusplus >= 201403L
   #define PINOCCHIO_WITH_CXX14_SUPPORT
+#elif defined(_MSVC_LANG)
+  #if _MSVC_LANG >= 201403L
+    #define PINOCCHIO_WITH_CXX14_SUPPORT
+  #endif
 #endif
 
-#if __cplusplus >= 201703L
-  #define PINOCCHIO_WITH_CXX17_SUPPORT
+#if __cplusplus >= 201103L
+  #define PINOCCHIO_WITH_CXX11_SUPPORT
+#elif defined(_WIN32)
+  #ifdef PINOCCHIO_WITH_CXX14_SUPPORT
+    #define PINOCCHIO_WITH_CXX11_SUPPORT
+  #endif
 #endif
 
 #define PINOCCHIO_STRING_LITERAL(string) #string