bpo-33608: Factor out a private, per-interpreter _Py_AddPendingCall(). (GH-11617)

This involves moving the global "pending calls" state to PyInterpreterState.

https://bugs.python.org/issue33608
diff --git a/Include/ceval.h b/Include/ceval.h
index 11283c0..9c6d420 100644
--- a/Include/ceval.h
+++ b/Include/ceval.h
@@ -221,7 +221,7 @@
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(int) _PyEval_SliceIndex(PyObject *, Py_ssize_t *);
 PyAPI_FUNC(int) _PyEval_SliceIndexNotNone(PyObject *, Py_ssize_t *);
-PyAPI_FUNC(void) _PyEval_SignalAsyncExc(void);
+PyAPI_FUNC(void) _PyEval_SignalAsyncExc(PyInterpreterState *);
 #endif
 
 /* Masks and values used by FORMAT_VALUE opcode. */