diff --git a/legacy/evil/src/lib/Evil.h b/legacy/evil/src/lib/Evil.h
index 1fbb30f306..ad8198116b 100644
--- a/legacy/evil/src/lib/Evil.h
+++ b/legacy/evil/src/lib/Evil.h
@@ -56,7 +56,9 @@ extern "C" {
 #endif
 
 
-#define WIN32_LEAN_AND_MEAN
+#ifndef WIN32_LEAN_AND_MEAN
+# define WIN32_LEAN_AND_MEAN
+#endif
 #include <windows.h>
 #undef WIN32_LEAN_AND_MEAN