Before this fix, unset variables lead to the following cmake configuration failure:
-- Found QT6
-- Using QT6 (6.2.1)
CMake Error at CMakeLists.txt:150 (if):
if given arguments:
"STREQUAL" "5.8.0" "OR" "STREQUAL" "5.7.1"
Unknown arguments specified
-- Configuring incomplete, errors occurred!Note that even with this