[AD] mouse cursors

[Matthew Leverton <meffer@xxxxxxxxxx>]

The available mouse pointers in 4.9 is very limited. I've updated my
copy of Allegro to support the attached list.

I don't really care if non-Windows operating systems don't support the
cursor, as I take that to mean the user isn't expecting such a cursor
to exist. In those cases, I would want the default cursor to show, but
I think the al_set_system_mouse_cursor() does nothing on an
unsupported cursor.

So in addition to adding support for the attached list, I would also
like to see <al_suggest_system_mouse_cursor(cursor_enum)>, which sets
the default cursor (CURSOR_ARROW) if the requested one isn't found.

I could supply a patch for Windows.

--
Matthew Leverton

typedef enum ALLEGRO_SYSTEM_MOUSE_CURSOR
{
   ALLEGRO_SYSTEM_MOUSE_CURSOR_NONE        =  0,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_ARROW       =  1,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_BUSY        =  2,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_QUESTION    =  3,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_EDIT        =  4,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_MOVE        =  5,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_RESIZE_WE   =  6,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_RESIZE_NS   =  7,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_RESIZE_NWSE =  8,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_RESIZE_NESW =  9,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_LOADING     = 10,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_CROSS       = 11,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_SELECT      = 12,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_SELECT_ALT  = 13,
   ALLEGRO_SYSTEM_MOUSE_CURSOR_NA          = 14,
   ALLEGRO_NUM_SYSTEM_MOUSE_CURSORS
} ALLEGRO_SYSTEM_MOUSE_CURSOR;