This is an implementation of function_ref, which has been proposed for
inclusion into C++23, but has not been accepted, yet, which is why we
place it in namespace qxp (for eXPerimental) instead of q23.
The implementation is based on wg21.link/P0792r9, which, at the time
of writing, is the latest revision of the paper. It will be used in
both QTestLib and qmldom.
Fixes: QTBUG-103739
Change-Id: I52723eca28f7ac02ce7ce51928361d81ae5c92b1
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
29b65c98e7