widl: Do not generate C structure for empty interfaces.

[André Hentschel]

On 26.06.2013 22:06, Thomas Faber wrote:
> On 2013-06-26 21:47, André Hentschel wrote:
>> The whitespace changes are bad, please don't do that.
> 
> Ok, I can take them out no problem.
> Why's it bad though? I thought the rule was "fix it while you're
> working on it anyway".
> 

Mostly because you mess up "git blame" output.
See also http://wiki.winehq.org/SubmittingPatches