Fix a few warnings
diff --git a/src/hb.hh b/src/hb.hh
index 18f4e5c..d604d95 100644
--- a/src/hb.hh
+++ b/src/hb.hh
@@ -468,7 +468,8 @@
 	  static inline T& operator |= (T &l, T r) { l = l | r; return l; } \
 	  static inline T& operator &= (T& l, T r) { l = l & r; return l; } \
 	  static inline T& operator ^= (T& l, T r) { l = l ^ r; return l; } \
-	}
+	} \
+	static_assert (true, "")
 
 /* Useful for set-operations on small enums.
  * For example, for testing "x ∈ {x1, x2, x3}" use: