diff --git a/utils/fgpanel/ApplicationProperties.cxx b/utils/fgpanel/ApplicationProperties.cxx
index 2b1baad77..d28159b58 100644
--- a/utils/fgpanel/ApplicationProperties.cxx
+++ b/utils/fgpanel/ApplicationProperties.cxx
@@ -16,6 +16,8 @@
 //  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
 
+#include <unistd.h>
+
 #include "ApplicationProperties.hxx"
 
 double