diff --git a/libguile/r6rs-ports.c b/libguile/r6rs-ports.c
index 2ee0ed939..4c78a867b 100644
--- a/libguile/r6rs-ports.c
+++ b/libguile/r6rs-ports.c
@@ -37,6 +37,7 @@
 #include "smob.h"
 #include "strings.h"
 #include "symbols.h"
+#include "syscalls.h"
 #include "values.h"
 #include "vectors.h"