Moving QT_XRB path setting to libxkbcommon, and fix 'set' in Qt5
This MR fixes the problem with the Qt5 and libxkb paths observed with the latest LCG releases (>=91)
Fixes ATLASVPONE-383 and ATLINFR-2218
This MR fixes the problem with the Qt5 and libxkb paths observed with the latest LCG releases (>=91)
Fixes ATLASVPONE-383 and ATLINFR-2218