vim-patch:7.4.312

Problem:    Cannot figure out what argument list is being used for a window.
Solution:   Add the arglistid() function. (Marcin Szamotulski)

https://code.google.com/p/vim/source/detail?r=v7-4-312

src/nvim/ex_docmd.c

@@ -5504,6 +5504,7 @@ void alist_new(void)
 {
   curwin->w_alist = xmalloc(sizeof(*curwin->w_alist));
   curwin->w_alist->al_refcount = 1;
+  curwin->w_alist->id = ++max_alist_id;
   alist_init(curwin->w_alist);
 }