diff --git a/src/serial.c b/src/serial.c
index 431a89bb5..c7944dae9 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -5,6 +5,7 @@
 #include <wchar.h>
 #include "86box.h"
 #include "ibm.h"
+#include "machine/machine.h"
 #include "io.h"
 #include "pic.h"
 #include "mem.h"