Add missing "static" modifiers for async-gen type structs.

Cython/Utility/AsyncGen.c

@@ -331,7 +331,7 @@ static __Pyx_PyAsyncMethodsStruct __Pyx_async_gen_as_async = {
 };
 #endif
 
-PyTypeObject __pyx_AsyncGenType_type = {
+static PyTypeObject __pyx_AsyncGenType_type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "async_generator",                          /* tp_name */
     sizeof(__pyx_PyAsyncGenObject),             /* tp_basicsize */
@@ -562,7 +562,7 @@ static __Pyx_PyAsyncMethodsStruct __Pyx_async_gen_asend_as_async = {
 };
 
 
-PyTypeObject __pyx__PyAsyncGenASendType_type = {
+static PyTypeObject __pyx__PyAsyncGenASendType_type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "async_generator_asend",                    /* tp_name */
     sizeof(__pyx_PyAsyncGenASend),                    /* tp_basicsize */
@@ -680,7 +680,7 @@ __Pyx_async_gen_wrapped_val_traverse(__pyx__PyAsyncGenWrappedValue *o,
 }
 
 
-PyTypeObject __pyx__PyAsyncGenWrappedValueType_type = {
+static PyTypeObject __pyx__PyAsyncGenWrappedValueType_type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "async_generator_wrapped_value",            /* tp_name */
     sizeof(__pyx__PyAsyncGenWrappedValue),            /* tp_basicsize */
@@ -949,7 +949,7 @@ static __Pyx_PyAsyncMethodsStruct __Pyx_async_gen_athrow_as_async = {
 };
 
 
-PyTypeObject __pyx__PyAsyncGenAThrowType_type = {
+static PyTypeObject __pyx__PyAsyncGenAThrowType_type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "async_generator_athrow",                   /* tp_name */
     sizeof(__pyx_PyAsyncGenAThrow),                   /* tp_basicsize */