moc parse error when tbb.h included

This was raised as https://bugreports.qt.io/browse/QTBUG-80990 and closed as duplicate of issue supposedly solved. It was not solved and still exists as of Qt 5.15.2. This happnes for TBB library versions 2020 and higher (up to current 2021).

It happens when Intel Thread Building Blocks (TBB) library is used within ang QT C++ source file processed by moc. So reproduction steps - add

#include <tbb/tbb.h>
into any C++ QT source file (i.e. the one processed by moc).

The reason for this is because TBB defines tbb::detail::dl:event structure with methods named emit() and this is what causing the issue.