Copy of the KDE4 macros. 

We "should" for some totally vague and unfathomable reason port our cmake code
the new and "better" way of doing stuff, using extra-cmake-modules. The
documentation for that porting step is completely incomplete and doesn't even
make any sort of case on why we should waste time that's better spent on
developing great application on futzing with build systems instead. So, skip
this bit of make-work churn.

http://api.kde.org/ecm/index.html#
https://techbase.kde.org/Development/ECM_SourceIncompatChanges#MacroAdditionalCleanFiles.cmake
