When rebuilding in the same build tree, build of widgets may fail since changes in cmake-app-template related to SPEC-2049.

The message was obscure and difficult to understand and describe. CMAKE emitted a message like "Deleting primary custom command output ...". In two words the creation of the widget failed because a test widget wasn't existing.

It only happens when rebuilding in the same bitbake working directory. This is why I set the priority to minor.

Fortunately is made a fix that I'm going to push in review.