diff --git a/examples/nettle-benchmark.c b/examples/nettle-benchmark.c
index 294028dd025b2da634bf7696b8d6411aa644c454..efef7007ee31496d1db64d0bc084e75b66f9aed4 100644
--- a/examples/nettle-benchmark.c
+++ b/examples/nettle-benchmark.c
@@ -37,7 +37,9 @@
 #include <time.h>
 
 /* For getopt */
-#include <unistd.h>
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#endif
 
 #include "aes.h"
 #include "arcfour.h"