match ivar lookup with osx and compatibility library

runtime.c

@@ -362,12 +362,11 @@ class_getInstanceVariable(Class cls, const char* name)
       while (cls != Nil)
 	{
 	  struct objc_ivar_list *ivarlist = cls->ivars;
-	  int i;
 
-	  if (NULL == ivarlist)
+	  if (ivarlist != NULL)
 	    {
-	      return NULL;
+	      int i;
-	    }
+
 	      for (i = 0; i < ivarlist->ivar_count; i++)
 		{
 		  Ivar ivar = &ivarlist->ivar_list[i];
@@ -377,6 +376,7 @@ class_getInstanceVariable(Class cls, const char* name)
 		      return ivar;
 		    }
 		}
+	    }
 	  cls = class_getSuperclass(cls);
 	}
     }