* add std.atomic.QueueMpsc.isEmpty
* make std.debug.global_allocator thread-safe
* std.event.Loop: now you have to choose between
- initSingleThreaded
- initMultiThreaded
* std.event.Loop multiplexes coroutines onto kernel threads
* Remove std.event.Loop.stop. Instead the event loop run() function
returns once there are no pending coroutines.
* fix crash in ir.cpp for calling methods under some conditions
* small progress self-hosted compiler, analyzing top level declarations
* Introduce std.event.Lock for synchronizing coroutines
* introduce std.event.Locked(T) for data that only 1 coroutine should
modify at once.
* make the self hosted compiler use multi threaded event loop
* make std.heap.DirectAllocator thread-safe
See #174
TODO:
* call sched_getaffinity instead of hard coding thread pool size 4
* support for Windows and MacOS
* #1194
* #1197