updated for version 7.4.312

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

src/main.c

@@ -322,6 +322,7 @@ main
     init_yank();		/* init yank buffers */
 
     alist_init(&global_alist);	/* Init the argument list to empty. */
+    global_alist.id = 0;
 
     /*
      * Set the default values for the options.