Where to put KDE Frameworks cmake stuff...

[Alexander Neundorf]

Hi,

so here's my proposal:

* we will have a separate KF5 package, which will be a build-time requirement 
for building KDE frameworks libraries. It will offer the following features
** KDE approved compiler settings
** KDE conforming install dirs
** finding consistent installations of the KDE frameworks libraries
** supporting a base and a shadowing KDE frameworks libraries installation 
(e.g. kcore from the system + kwidgets from the user, shadowing the kwidgets 
from the system)

* every KDE Frameworks library will depend at build-time on this KF5 package

* every KDE Frameworks library will install a KFooConfig.cmake file, which 
will have neither dependencies to e-c-m nor to KF5

* any application is free to use the installed KFooConfig.cmake files directly 
without introducing any additional dependencies: find_package(KFooConfig 
NO_MODULE)

* there will be a FindKF5.cmake, which every application must use which wants 
to get the full KDE features, like install dirs etc., All the KDE frameworks 
libraries will be known to FindKF5.cmake as components:
find_package(KF5 MODULE COMPONENTS kcore kwidgets)
This will provide the set of install dirs, compiler flags, ensuring that 
libraries are found which are compatible.

* by installing a KF5 to some prefix, this prefix is "marked" as an install 
location of KDE frameworks. Every KDE frameworks library which is built 
against this KF5, must use the same install prefix. By doing this, it will get 
the same set of install locations as have been set when KF5 has been 
installed. This should ensure that a consistent set of KDE frameworks 
libraries is found later.

* KF5 will provide a file KF5BuildSpecs, which should be used by KDE 
frameworks libraries. This provides: a common required cmake version (so we 
can rely on features and behaviour), a common required e-c-m version, and 
common version numbers. All these are only active if the using library does 
include(KF5BuildSpecs) and then actually uses the provided variables.


This will also mean that the kde-modules/ subdir from e-c-m will go away, this 
will be in the KF5 package. Then we have a clear separation of stuff again.


Comments ?

I have an almost complete example around, I'll post it in the next days here.

Alex