Requiring cmake 2.8.9 for kdelibs 4.10 ?

[Stephen Kelly]

Alexander Neundorf wrote:

> To make it short, when upgrading CMake, and causing some pain by this, I'd
> like to have the maximum outcome of it, i.e. the most recent version
> possible.

To meet that goal, I would suggest bumping to CMake 2.8.11 instead when it's 
out and for the appropriate KDE 4 release.

That version will have everything we'll need and want for KDE Frameworks 
hopefully:

http://community.kde.org/Frameworks/Epics/CMake_target_usage_requirements#TODO

If we depend on that version we can make our buildsystem changes (in repos 
which are not kdelibs) orthogonally to our Qt changes. That is, we can port 
KDE 4 to a KDE-Frameworks-quality buildsystem:

 * We won't need to link to qtmain.lib on Windows. The need for that will be 
encoded in the Qt4::Core imported target.
 * We won't need to use include_directories() for Qt or kdelibs includes 
anywhere. That information will be encoded in the Qt and kdelibs imported 
targets. For non-Qt non-KDE dependencies we can also look into adding 
IMPORTED targets to their find files too.
 * We can use qt4_use_modules() extensively or exclusively, simplifying the 
port to KDE frameworks on the build system side to changing that to 
qt5_use_modules with a sed script. We can add a similar macro/function for 
kdelibs stuff with also a simple 4 -> 5 when porting.

In short - I'd like the KDE 4 CMake dependency to be the same as the minimum 
functional and featureful KDE Frameworks CMake dependency to orthogonalize 
ease the porting effort to modern 'target orientated' CMake and away from 
'directory orientated' design which we currently have.

I would like that eventually. Not necessarily as soon as CMake 2.8.11 is 
out.

For kdelibs 4.10, I think it's a good idea to bump the CMake requirement to 
at least 2.8.7 so that we can port away from automoc4 already etc. That's 
also 'old' enough that recent releases of distros (current Ubuntu at least) 
already have it. 

So from the building kde stuff point of view it should be relatively 
painless, and we free ourselves from the silly restrictions we have by 
having CMake 2.8.6 as the minimum required version, such as not being able 
to use CMAKE_CURRENT_LIST_DIR etc.

Thanks,

Steve.