Hi,

in KDE 4.2 we have quite a few changes regarding the buildsystem compared to 4.0/4.1. Also we require at least CMake 2.6.2 now, which alone brings a lot of new features.

So, if you want to know what has changed, IOW, if you are a
KDE developer or a packager or somebody writing about it, you can find a (hopefully) full list on TechBase:
Changes in the buildsystem with KDE 4.2.

Alex