ddraw: Allow creating back buffer for pre-DirectX 7 interfaces.

[James McKenzie]

Austin English wrote:
> 2010/7/19 Oldřich Jedlička <oldium.pro at seznam.cz>:
>   
>> The tests will be a problem, because I don't have the Windows machine as a
>> reference. Also `make test` fails on DirectX tests for me because of r600
>> driver bug...
>>
>> When I write CreateSurface tests (for various interfaces), is there a way for
>> me to run the tests on Windows? I have a Windows XP machine at work.
>>     
>
> If you have mingw installed, you can use 'make crosstest' to make a
> test executable that will run on windows.
>
>   
Don't forget that we have the testbot available as well, for comparing 
your tests against many versions of Windows (thanks Ge.)

James McKenzie