Arch Linux

## Description:

Qt Wayland clients do not respond to mouse input on Qt-based compositors.

## Additional info:

package version(s):

- qt5-wayland 5.9.1-2
- qt5-base 5.9.1-3

## Steps to reproduce:

Run the attached minimal compositor as an X client with

$ qmlscene minimal-compositor.qml -platform xcb

Then run a Qt client with the wayland backend, I.e. the attached rectangle.qml

$ qmlscene rectangle-mousearea.qml -platform wayland

Try to click the green in the window

### Expected result:

The green window should turn blue when you click it.

You should also be able to drag the window around the screen.

### Actual result:

Nothing happens, and you're not able to move the window.

## Probably not a compositor bug, can't reproduce outside PKGBUILD

I tried building Qt manually with the same source packages that arch uses, the same patches and most of the same configure options:

./configure -confirm-license -opensource -v
-nomake tests
-developer-build
-plugin-sql-psql
-plugin-sql-mysql
-plugin-sql-sqlite
-plugin-sql-odbc
-plugin-sql-ibase
-system-sqlite
-openssl-linked
-nomake examples
-optimized-qmake
-dbus-linked
-system-harfbuzz
-journald
-no-use-gold-linker
-reduce-relocations

I.e. I removed the `-no-rpath`, `-prefix` and other path flags and added `-developer-build`.

And I did not experience the issue with the resulting build. Also, I see the issue when I run system-version Qt clients on Qt compositors built manually, but not the other way around. Non-qt clients also run fine.

I can also see the mouse events being passed over the Wayland protocol when running QT_WAYLAND_DEBUG=1.

I also tried with non-qml clients, so the bug is not related to qtdeclarative.

As long as this is an Arch-only bug, I don't have the time to look further into it.