diff --git a/util/hb-subset.cc b/util/hb-subset.cc
index 21d0f767b2af4453c12a6fb3e3226a531553d5b3..2306e66ad77ce7384eb0fa20dfcd44d2fdb7a65c 100644
--- a/util/hb-subset.cc
+++ b/util/hb-subset.cc
@@ -25,7 +25,9 @@
  * Google Author(s): Garret Rieger, Rod Sheeter
  */
 
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 
 #include "main-font-text.hh"
 #include "hb-subset.h"