It's required by the standard, see e.g. [1] and the eel.is links in
the code.
[ChangeLog][QtCore][QPartialOrdering] Added three-way comparison
operator (<=>) against literal zero, available when compiling in C++20
mode.
[1] https://en.cppreference.com/w/cpp/utility/compare/partial_ordering#Comparisons
Change-Id: I8a3b76661400930c6e247cf5b138ff52bf784395
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
c39fff0da5