Scan outside the build directory was possible on mac and windows.
Avoid it by checking the relative path to the build directory.
Change-Id: I6a7082998429f902745146446bf89fc0cc75ca54
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
(cherry picked from commit bdd7fcbac2)
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>