diff --git a/merge-recursive.c b/merge-recursive.c
index 8ad4be8..4b0884b 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -5,6 +5,7 @@
  */
 #include "advice.h"
 #include "cache.h"
+#include "lockfile.h"
 #include "cache-tree.h"
 #include "commit.h"
 #include "blob.h"