possible race fix in Worker

src/backend/common/Worker.h

@@ -20,6 +20,9 @@
 #define XMRIG_WORKER_H
 
 
+#include <atomic>
+
+
 #include "backend/common/interfaces/IWorker.h"
 
 
@@ -36,7 +39,7 @@ protected:
     inline size_t id() const override                       { return m_id; }
     inline uint32_t node() const                            { return m_node; }
 
-    uint64_t m_count                = 0;
+    std::atomic<uint64_t> m_count                = {0};
 
 private:
     const int64_t m_affinity;