Qt : Use legacy xcb tablet coordinates
Qt : Use legacy xcb tablet coordinates

Works around an issue with 5.12+ when using a wacom tablet on linux.
This generally results in clicks being misplaced and drag operations
behaving erratically.

See:

   https://bugreports.qt.io/browse/QTBUG-77826
   https://github.com/linuxwacom/xf86-input-wacom/issues/93

This can hopefully be removed once this patch is in:

   https://codereview.qt-project.org/c/qt/qtbase/+/284141

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