Recommended patches for Qt 6.8

[Christophe Marin]

Hello,

A couple regressions affecting Plasma were found in Qt 6.7.3, and some of those 
are still present in 6.8.0.

- https://bugs.kde.org/493116 needs 2 changes in qtdeclarative and one in 
qtbase to build:
https://code.qt.io/cgit/qt/qtbase.git/commit/?id=2ea3abed01
https://code.qt.io/cgit/qt/qtdeclarative.git/commit/?id=3330731d0c
https://code.qt.io/cgit/qt/qtdeclarative.git/commit/?id=2aefbca84d

- If you're making packages for x86, you will likely see failure in 
qtmultimedia.
https://build.opensuse.org/projects/home:krop:Qt6:Release/packages/qt6-multimedia/files/0001-Fix-build-on-x86-arch.patch?expand=1 adresses this. I'll 
submit upstream later.

- qtquick3d doc creation fails if your distro doesn't have openXR (https://
bugreports.qt.io/browse/QTBUG-129807).
Workaround if you're affected, use `-DFEATURE_quick3dxr_openxr:BOOL=OFF -
DFEATURE_system_openxr:BOOL=OFF`  when building docs

- If you don't use the patch yet, adding 
https://code.qt.io/cgit/qt/qtwayland.git/commit/?id=c2f61bc4 to qtwayland will 
fix some warnings (needs a path change to apply to 6.8)

- https://bugreports.qt.io/browse/QTBUG-129622 is still present in 6.8.0, but 
thanks to Nicolas, there's now a testcase and the commit causing the issue was 
identified.

If you're planning to stick to 6.7.3 for the moment, you may also be 
interested in https://code.qt.io/cgit/qt/qtbase.git/commit/?id=d3780f2444

HTH
Christophe