Eryk:
> SleepConditionVariableSRW() can't be interrupted in PyCOND_WAIT() and PyCOND_TIMEDWAIT().

Oh. A comment on StackOverlow says:     

"The WaitForXxx functions accept parameters of the generic HANDLE type, which represents a handle to a kernel object. Condition variables are user-mode objects, not kernel objects, so you cannot use them with these functions, since they work only with kernel objects."

https://stackoverflow.com/questions/37522108/can-you-really-wait-on-condition-variable-with-waitfor-objects

I only created this issue because of this comment in pycore_condvar.h:
---
/* non-emulated condition variables are provided for those that want
 * to target Windows Vista.  Modify this macro to enable them.
 */
#ifndef _PY_EMULATED_WIN_CV
#define _PY_EMULATED_WIN_CV 1  /* use emulated condition variables */
#endif
---