[Wayland] GTK theme gets loaded when the Wayland plugin is used, and tries to connect to X

Hi.

I am building QT 5 from GIT, I have tried release, and then the stable branch. With both, I have tried to run a sample with the Wayland backend, however the issue is that they also try to connect to an xserver.

With weston, it uses xwayland, so it gets worked around, but when I unset DISPLAY I get a GTK error, that it can not connect to an Xserver.

After asking on the IRC, it has been determined that QT is using the gtk style when this error happens, and when I pass -style fusion to the QT sample, it is able to run on Wayland without DISPLAY being set.