Enable constexpr support for Visual Studio 2017

Change-Id: I894789c41cc2c1a327c14d0526e658520d096085
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qcompilerdetection.h

@@ -931,6 +931,9 @@
 #      define Q_COMPILER_THREADSAFE_STATICS
 #      define Q_COMPILER_UNIFORM_INIT
 #    endif
+#    if _MSC_VER >= 1910
+#      define Q_COMPILER_CONSTEXPR
+#    endif
 #  endif /* __cplusplus */
 #endif /* Q_CC_MSVC */
 

src/corelib/thread/qbasicatomic.h

@@ -78,6 +78,9 @@
 #  error "Qt has not been ported to this platform"
 #endif
 
+QT_WARNING_PUSH
+QT_WARNING_DISABLE_MSVC(4522)
+
 QT_BEGIN_NAMESPACE
 
 #if 0
@@ -340,4 +343,6 @@ public:
 
 QT_END_NAMESPACE
 
+QT_WARNING_POP
+
 #endif // QBASICATOMIC_H