This method was removed in e015a43b51
However, it was not exactly *unused* as the commit message would say.
This method was the only thing that allowed spin_until to exit when
the event loop was cancelled. This happens normally when IPC connections
are closed, but also when the process is killed.
The logic to properly handle process exit from event loop spins needs to
actually notify the caller that their goal condition was not met though.
That will be handled in a later commit.
Move some more complex globals into a Singleton, which allows it being
used from global destructors. It solves problems where some global
variables, such as HashMaps may already be deleted, triggering crashes
trying to use them.
This allows adding and removing of asynchronous signal handlers while
executing signal handlers, even if it is for the same signal that is
being handled right now.
