Use the macros provided by KDesignerPlugin
Review Request #118193 - Created May 18, 2014 and submitted
Use the macros provided by KDesignerPlugin This also removes the RPath settings, as they are entirely unnecessary (and arguably not correct, since we are linking against a library that is locally built).
Builds, installs, added an arrow button to a form in designer.
Does not build here: CMake complains that kf5designerplugin_add_plugin() does not exist. If I replace it with kf5designerplugin_add_widget_files() then it says "Cannot specify link libraries for target "kdedeprecated" which is not built by this project."