Move Explicit

src/libutil/types.hh

@@ -34,4 +34,16 @@ struct OnStartup
     OnStartup(T && t) { t(); }
 };
 
+/* Wrap bools to prevent string literals (i.e. 'char *') from being
+   cast to a bool in Attr. */
+template<typename T>
+struct Explicit {
+    T t;
+
+    bool operator ==(const Explicit<T> & other) const
+    {
+        return t == other.t;
+    }
+};
+
 }