3 build system patches for 3.5.

[Caleb Tennis]

>
> I'm fine with the switch, but out of curiosity, what's the reason  
> you don't
> want it in?
>
>

We (the Gentoo packagers) are attempting to address every build time  
dependency with a configure switch.  The reason is because many KDE  
features are auto detected, but don't offer a "yes/no" option at  
configure time - so you may not even deterministically know that you  
have some feature set built in, meaning that if you upgrade something  
in the background it can potentially break.  We're just trying to  
make sure that the option exists to turn features off, even if you  
have the underlying support for them installed.