diff --git a/builtin/patch-id.c b/builtin/patch-id.c
index 81552e0..970d0d3 100644
--- a/builtin/patch-id.c
+++ b/builtin/patch-id.c
@@ -1,4 +1,5 @@
 #include "builtin.h"
+#include "config.h"
 
 static void flush_current_id(int patchlen, struct object_id *id, struct object_id *result)
 {