As suggested in ECM documentation.

Otherwise Qt5Designer_FOUND in src/designer/CMakeLists.txt is always
false and the corresponding code never built.

This is the beginning of revision history for this module. If you
want to look at revision history older than this, please refer to the
techbase wiki for how to use Git history grafting. At the time of
writing, this wiki is located here:

http://community.kde.org/Frameworks/GitOldHistory

If you have already performed the grafting and you don't see any
history beyond this commit, try running "git log" with the "--follow"
argument.

Branched from the monolithic repo, kdepim master branch, at commit
d0009536f24e8c7f4cc32a70936f5c25194e9a6f