The changed thread code may not wish to save the old context under certain circumstances but thread-unix.c assumed it would, cached it and used it unconditionally.
Also, prevent it from leaking away all the jump buffers (old problem). Creating and removing threads would eventually run it out of buffers and then it would crash after that. Plugins, like Pictureflow, which have worker threads could only be started a few times. Implement a simple O(1) allocator that will reuse them and stays self-contained to its own types (as it appears the original author intended).
6ed0087: Base scheduler queues off linked lists and do cleanup/consolidation
Abstracts threading from itself a bit, changes the way its queues are handled and does type hiding for that as well.
Do alot here due to already required major brain surgery.
Threads may now be on a run queue and a wait queue simultaneously so that the expired timer only has to wake the thread but not remove it from the wait queue which simplifies the implicit wake handling.
List formats change for wait queues-- doubly-linked, not circular. Timeout queue is now singly-linked. The run queue is still circular as before.
Adds a better thread slot allocator that may keep the slot marked as used regardless of the thread state. Assists in dumping special tasks that switch_thread was tasked to perform (blocking tasks).
Deletes alot of code yet surprisingly, gets larger than expected. Well, I'm not not minding that for the time being-- omlettes and break a few eggs and all that.