Well, I ping my view that we should:

1) Add general atfork() mechanism.
2) Dive into the std lib and add handlers one by one, that depending on case, either do the lock/init thing or just init the state of the library to some valid state in the child.

Once this mechanism is in place and committed with a few obvious handlers such as the one for the logging library, other handlers can be added over time.

Following this path we will slowly resolve the problem, handler by handler, without introducing the invalid state problem.