Fix qmake module generation for Qt 5.12.1
Summary:
Patch by Eike Ziller from https://github.com/KDAB/GammaRay/pull/526 in
response to Qt change https://codereview.qt-project.org/#/c/248684/.
Reviewers: apol
Reviewed By: apol
Subscribers: kde-frameworks-devel, kde-buildsystem
Tags: Frameworks, Build System
Differential Revision: https://phabricator.kde.org/D18243