diff --git a/libguile/sort.c b/libguile/sort.c
index be29e6710..f5e3a3f65 100644
--- a/libguile/sort.c
+++ b/libguile/sort.c
@@ -80,6 +80,7 @@ char *alloca ();
 #include "unif.h"
 #include "ramap.h"
 #include "alist.h"
+#include "feature.h"
 
 #include "sort.h"