diff --git a/libs/ardour/find_session.cc b/libs/ardour/find_session.cc
index e10a155aa0..eb6e7c1051 100644
--- a/libs/ardour/find_session.cc
+++ b/libs/ardour/find_session.cc
@@ -19,7 +19,9 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 
 #include <cstring>
 #include <climits>