Generate and use export header for libkdecoration
completed by: Jacob Logan
mentors: Martin Gräßlin
The kdecoration library is currently using the old and deprecated KDE_EXPORT macro. An own export header for kdecoration should be generated in CMake and used for the exports in this library.
To complete this task a build environment of kde-workspace master branch is needed. This can be time consuming, ensure to have a setup before starting working on this task