Breeze version 5.9.3 has what seems flawed logic about including the QQuickWindow headerfile: it is included only when building for KDE4, but the corresponding type is used only when *not* building for KDE4. In addition the headerfile is only included when X11 is available. As a result, Breeze 5.9.3 fails to build for KF5 on Mac, yet this is supposed to be possible (and even somewhat supported) judging from the CMake files. I think the headerfile should simply be included unconditionally. Or, alternatively the build system could exclude all files that contain only windowmanager code on Mac and MS Windows (if that doesn't affect MDI windows).
Git commit 148c4c65af5dd309a58f6f74f74613d9d92409b6 by Hugo Pereira Da Costa. Committed on 22/08/2017 at 20:19. Pushed by hpereiradacosta into branch 'master'. moved inclusion of QQuickWindow and QQuickItem outside of X11 block M +6 -2 kstyle/breezewindowmanager.cpp https://commits.kde.org/breeze/148c4c65af5dd309a58f6f74f74613d9d92409b6