When reconfiguring Qt it can give an error saying that the DUMMY platform is unsupported

When reconfiguring Qt it can give an error saying that the dummy platform is unsupported. This can happen if you reconfigure on a day different to the initial configure as it will go into the line:

!isEqual(QMAKE_LICHECK_TIMESTAMP, $$today) {

in default_pre.prf and this will fail, thus causing it to run the qmake check here. However at this point the variable - QMAKE_XSPEC - is set to dummy, and therefore it fails to run licheck as a result.