diff --git a/libraries/liblutil/sockpair.c b/libraries/liblutil/sockpair.c
index 6caa3b0aad..b8c7b2bd25 100644
--- a/libraries/liblutil/sockpair.c
+++ b/libraries/liblutil/sockpair.c
@@ -5,6 +5,7 @@
 
 #include "portable.h"
 #include <ac/socket.h>
+#include <ac/unistd.h>
 
 #include <lutil.h>