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/buffer_defs.h

@@ -255,6 +255,7 @@ struct wininfo_S {
 typedef struct arglist {
   garray_T al_ga;               /* growarray with the array of file names */
   int al_refcount;              /* number of windows using this arglist */
+  int id;                       ///< id of this arglist
 } alist_T;
 
 /*