Avoid an "unused function" warning of the C compiler.

Cython/Utility/Coroutine.c

@@ -1449,6 +1449,7 @@ static PyTypeObject __pyx_CoroutineAwaitType_type = {
 #endif
 };
 
+#if PY_VERSION_HEX < 0x030500B1 || __Pyx_IterableCoroutine_USED || CYTHON_USE_ASYNC_SLOTS
 static CYTHON_INLINE PyObject *__Pyx__Coroutine_await(PyObject *coroutine) {
     __pyx_CoroutineAwaitObject *await = PyObject_GC_New(__pyx_CoroutineAwaitObject, __pyx_CoroutineAwaitType);
     if (unlikely(!await)) return NULL;
@@ -1457,6 +1458,7 @@ static CYTHON_INLINE PyObject *__Pyx__Coroutine_await(PyObject *coroutine) {
     PyObject_GC_Track(await);
     return (PyObject*)await;
 }
+#endif
 
 #if PY_VERSION_HEX < 0x030500B1
 static PyObject *__Pyx_Coroutine_await_method(PyObject *coroutine, CYTHON_UNUSED PyObject *arg) {
@@ -1464,6 +1466,7 @@ static PyObject *__Pyx_Coroutine_await_method(PyObject *coroutine, CYTHON_UNUSED
 }
 #endif
 
+#if __Pyx_IterableCoroutine_USED || CYTHON_USE_ASYNC_SLOTS
 static PyObject *__Pyx_Coroutine_await(PyObject *coroutine) {
     if (unlikely(!coroutine || !__Pyx_Coroutine_Check(coroutine))) {
         PyErr_SetString(PyExc_TypeError, "invalid input, expected coroutine");
@@ -1471,6 +1474,7 @@ static PyObject *__Pyx_Coroutine_await(PyObject *coroutine) {
     }
     return __Pyx__Coroutine_await(coroutine);
 }
+#endif
 
 static PyObject *
 __Pyx_Coroutine_get_frame(CYTHON_UNUSED __pyx_CoroutineObject *self, CYTHON_UNUSED void *context)