[cmake-developers] Review request: fix-Qt5-windows-build

[Stephen Kelly]

Hi,

I didn't follow the encoding work done by Clinton, and in my Qt 5 build with 
default settings, the new codepage related definition is not set. However, 
if it is set somehow, then the build would be calling methods which are not 
present in Qt 5. 

I've just pushed a topic fixing that, but would appreciate review from 
Clinton?

Thanks,

Steve.