Fix lazy delegate type resolution across modules

lynglib/stdlib/lyng/root.lyng

@@ -415,26 +415,24 @@ fun with<T,R>(self: T, block: T.()->R): R {
     block(self)
 }
 
-extern fun __builtinLazy(creator: Object): Object
-
 /*
     Standard implementation of a lazy-initialized property delegate.
     The provided creator lambda is called once on the first access to compute the value.
     Can only be used with 'val' properties.
 */
 class lazy<T,ThisRefType=Object>(creatorParam: ThisRefType.()->T) : Delegate<T,ThisRefType> {
-    private val delegate: Delegate<T,ThisRefType> = __builtinLazy(creatorParam) as Delegate<T,ThisRefType>
+    private val creator: ThisRefType.()->T = creatorParam
+    private var value = Unset
 
     override fun bind(name: String, access: DelegateAccess, thisRef: ThisRefType): Object {
-        delegate.bind(name, access, thisRef)
+        if (access != DelegateAccess.Val) throw "lazy delegate can only be used with 'val'"
+        this
     }
 
     override fun getValue(thisRef: ThisRefType, name: String): T {
-        delegate.getValue(thisRef, name) as T
-    }
-
-    override fun setValue(thisRef: ThisRefType, name: String, newValue: T): void {
-        delegate.setValue(thisRef, name, newValue)
+        if (value == Unset)
+            value = with(thisRef, creator)
+        value as T
     }
 }