basic threading support missing

[djoume]

Steps to reproduce:

import threading

def task():
    print("hello")

thread = threading.Thread(target=task)
print("starting thread")
thread.start()
print("joining thread")
thread.join()
print("END")

Expected (CPython behaviour)

starting thread
hello
joining thread
END

Actual:

starting thread
Traceback (most recent call last):
  File <string>, line 8, in <module>
  File VFS.threading.py, line 995, in start
    if _sys.flags.thread_inherit_context:
AttributeError: 'flags' object has no attribute 'thread_inherit_context'