gdi32: Use 0xffff as a default character as Vista does

[Dmitry Timoshkov]

"Reece Dunn" <msclrhd at googlemail.com> wrote:

>> +        TM.tmDefaultChar = pOS2->usDefaultChar ? pOS2->usDefaultChar : 0xffff;
> 
> There is a UNICODE_NOCHAR constant for this.

UNICODE_NOCHAR is defined in winuser.h, we can't use it in gdi32.

-- 
Dmitry.