Add CPU core count to log files

src/common/x64/cpu_detect.h

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <optional>
 #include <string_view>
 #include "common/common_types.h"
 
@@ -74,4 +75,7 @@ struct CPUCaps {
  */
 const CPUCaps& GetCPUCaps();
 
+/// Detects CPU core count
+std::optional<int> GetProcessorCount();
+
 } // namespace Common