diff --git a/common/rfb/util.h b/common/rfb/util.h
index e9114c3..0de64c4 100644
--- a/common/rfb/util.h
+++ b/common/rfb/util.h
@@ -38,6 +38,10 @@
 #  define __printf_attr(a, b)
 #endif // __GNUC__
 
+#ifndef __unused_attr
+#  define __unused_attr __attribute((__unused__))
+#endif
+
 namespace rfb {
 
   // -=- Class to handle cleanup of arrays of characters