onclick events don't work when using the mouse

[gebausim]

https://bugs.webkit.org/show_bug.cgi?id=290758

As in the WebKit issue, the commit that added support for auxevents broke cogs wayland backend. Now when using the mouse auxevents are fired for every mouse button.

[gebausim]

#760 fixes the left and middle mouse buttons but when right clicking all buttons stop working (like in #704)

[grybouilli]

It seems like mouse events don't work on DRM backend either

[gebausim]

The right click issue can be fixed by compiling WPEWebKit with ENABLE_CONTEXT_MENUS set to OFF.