work with PIThreadPoolWorker

libs/main/thread/pithreadpoolexecutor.h

@@ -1,6 +1,10 @@
+#ifndef PITHREADPOOLEXECUTOR_H
+#define PITHREADPOOLEXECUTOR_H
+
 #include "pithreadpoolworker.h"
 
 namespace {
-// [[deprecated("DeprecatedHeader.h is deprecated. Use NewHeader.h instead.")]]
 DEPRECATEDM("Use pithreadpoolworker.h") const bool deprecated_header_is_used = true;
-} // namespace
+}
+
+#endif