There is an empty file called 'empty.cpp' in the directory generators/spectre/conf. It came in 2007 along with the spectre generator, and has not been touched ever since. Is there a reason not to simply remove it?
Git commit 59b87705454b4a7a53b1cb9a6d8b0c619d02beda by Albert Astals Cid, on behalf of Oliver Sander. Committed on 14/08/2018 at 08:18. Pushed by aacid into branch 'master'. Remove unused file D +0 -0 generators/spectre/conf/empty.cpp https://commits.kde.org/okular/59b87705454b4a7a53b1cb9a6d8b0c619d02beda