vim-patch:7.4.1559

Problem:    Passing cookie to a callback is clumsy.
Solution:   Change function() to take arguments and return a partial.

1735bc988c

src/nvim/normal.c

@@ -2466,7 +2466,7 @@ do_mouse (
                            (int) strlen(tab_page_click_defs[mouse_col].func),
                            &rettv, ARRAY_SIZE(argv), argv,
                            curwin->w_cursor.lnum, curwin->w_cursor.lnum,
-                           &doesrange, true, NULL);
+                           &doesrange, true, NULL, NULL);
           clear_tv(&rettv);
           break;
         }