Use a EStatusBits 'enum' instead of a 'constexpr static int' (allowing...

Use a EStatusBits 'enum' instead of a 'constexpr static int' (allowing automatic checking for overlaps)

core/thread/inc/TWin32Mutex.h

@@ -36,7 +36,9 @@ friend class TWin32Condition;
 private:
    CRITICAL_SECTION fCritSect;
 
-   constexpr static int kIsRecursive = BIT(14);
+   enum EStatusBits {
+      kIsRecursive = BIT(14);
+   }
 
 public:
    TWin32Mutex(Bool_t recursive=kFALSE);