vim-patch:7.4.369

Problem:    Using freed memory when exiting while compiled with EXITFREE.
Solution:   Set curwin to NULL and check for that. (Dominique Pelle)

https://code.google.com/p/vim/source/detail?r=v7-4-369

src/nvim/window.c

@@ -2001,6 +2001,10 @@ void win_free_all(void)
 
   while (firstwin != NULL)
     (void)win_free_mem(firstwin, &dummy, NULL);
+
+  // No window should be used after this. Set curwin to NULL to crash
+  // instead of using freed memory.
+  curwin = NULL;
 }
 
 #endif