[AD] non blocking menu bug

[jcugniere@xxxxxxxxxx]

Hello,

It seems there is a little bug with non blocking menus, where allegro will crash
if you try to shutdown a dialog player while there is a menu player still
active. Attached are a test program (run it, open a menu and press some keys
without closing the menu), as well a simple fix.

The fix should be reviewed, because I'm not 100% sure it catches every variant
of the bug (for example what if the user creates an unrelated menu_player on his
own ?).

-- 
Julien Cugnière

Attachment: menu.diff
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Attachment: bugmenu.c
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