diff --git a/contrib/db/libmdbx/src/osal.h b/contrib/db/libmdbx/src/osal.h
index 4b15a942..c1f645bb 100644
--- a/contrib/db/libmdbx/src/osal.h
+++ b/contrib/db/libmdbx/src/osal.h
@@ -89,7 +89,9 @@
 #endif
 
 #if defined(_WIN32) || defined(_WIN64)
-#d)(efine WIN32_LEAN_AND_MEAN
+#ifndef WIN32_LEAN_AND_MEAN
+  #define WIN32_LEAN_AND_MEAN
+#endif
 #include <tlhelp32.h>
 #include <windows.h>
 #include <winnt.h>