diff --git a/linker/linker.h b/linker/linker.h
index 301d26805..8a5bc4515 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -95,6 +95,8 @@ struct soinfo
     unsigned base;
     unsigned size;
 
+    int unused;  // DO NOT USE, maintained for compatibility.
+
     unsigned *dynamic;
 
     unsigned wrprotect_start;