build: ensure Qt qIsNaN macro available where its needed
build: ensure Qt qIsNaN macro available where its needed

Resolves https://github.com/performancecopilot/pcp/issues/707

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp