diff --git a/src/ffisyms.cc b/src/ffisyms.cc
index b82e23bd4a7d8cf14f3c841300501444f8aa143b..a4f8eb1dd722c70bcc3083e5c0871aa40b3e19d8 100644
--- a/src/ffisyms.cc
+++ b/src/ffisyms.cc
@@ -4,8 +4,9 @@
 #include <box/tuple.h>
 #include <box/lua/index.h>
 #include <box/lua/call.h>
-#include <readline/readline.h>
 #include <lua/init.h>
+#include <stdio.h>
+#include <readline/readline.h>
 
 /*
  * A special hack to cc/ld to keep symbols in an optimized binary.