Application hang on exit

This is an application hang during exit, involving destruction of Q_GLOBAL_STATICs, one of them being the QDBusConnectionManager. It can be triggered by the included trivial example. I have tested it on Linux with Breeze style. Oxygen also "works". GTK+ style does not reproduce the bug. Also included: backtrace of the example where it hangs, a helgrind log of the same example, and a patch that I've tried to fix the problem. With the commented out lines in the patch not commented out, the test application won't hang, but blocking queued signals won't be delivered to a thread that is just starting, which breaks other things.