[KDE/Mac] Fixing graphics problems in KDE/Qt on Apple OS X

[Nicolas Pavillon]

Hello, 

Considering the different points brought about that, it seems that several options are not really viable. 

The /.MacOSX/environment.plist approach is not really acceptable as it sets something globally. Furthermore, it is supposedly not
supported on later platforms, and would require to install files outside of Macports directories, which is to be avoided. 

The settings through the application plist file seemed elegant to me, but it seems not reliable depending on platforms, and would 
probably become a hassle in its implementation, where plist files would have to be changed, possibly up to the cmake port. 

In light of this, Ian, if you find a place where it would be possible to patch kdelibs4 to get it done, it would be probably far simpler.
And even if it is not possible to push it upstream, we could keep the patch downstream for Mac-specific applications. Kdelibs4 is
already patched at several places already. Not the best solution in principle, but apparently the simplest in practice. 

> Note: if we can go with one of my three options, it is not necessary to install
> with +raster.  They all override the installation option.  

This is a very good point. It would make things really easier, as it is not possible to require specific variants in Macports. 

Cheers, 

Nicolas