diff --git a/clients/riscos/Manager.cpp b/clients/riscos/Manager.cpp
index a18a24c3e1..7b72cd7e74 100644
--- a/clients/riscos/Manager.cpp
+++ b/clients/riscos/Manager.cpp
@@ -21,6 +21,7 @@
 */
 
 #include <unistd.h> // for usleep
+#include <config.h> // for usleep on non-linux platforms
 
 #include <qpainter.h>
 #include <qimage.h>