Add missing DLL exports for pyo3-specific symbols

Related #456

Author: msimacek

graalpython/com.oracle.graal.python.cext/src/listobject.c

@@ -132,7 +132,7 @@ PyTypeObject PyList_Type = {
 };
 
 // alias for internal function, currently used in PyO3
-void _PyList_SET_ITEM(PyObject* a, Py_ssize_t b, PyObject* c) {
+PyAPI_FUNC(void) _PyList_SET_ITEM(PyObject* a, Py_ssize_t b, PyObject* c) {
     return PyList_SET_ITEM(a, b, c);
 }
 

graalpython/com.oracle.graal.python.cext/src/object.c

@@ -2546,7 +2546,7 @@ Py_ssize_t PyTruffle_REFCNT(PyObject *obj) {
 }
 
 // alias, currently used in PyO3
-Py_ssize_t _Py_REFCNT(PyObject *obj) {
+PyAPI_FUNC(Py_ssize_t) _Py_REFCNT(PyObject *obj) {
     return PyTruffle_REFCNT(obj);
 }
 
@@ -2589,7 +2589,7 @@ PyTypeObject* PyTruffle_TYPE(PyObject *a) {
 }
 
 // alias, currently used in PyO3
-PyTypeObject* _Py_TYPE(PyObject *obj) {
+PyAPI_FUNC(PyTypeObject*) _Py_TYPE(PyObject *obj) {
     return PyTruffle_TYPE(obj);
 }
 
@@ -2625,7 +2625,7 @@ Py_ssize_t PyTruffle_SIZE(PyObject *ob) {
 }
 
 // alias, currently used in PyO3
-Py_ssize_t _Py_SIZE(PyObject *obj) {
+PyAPI_FUNC(Py_ssize_t) _Py_SIZE(PyObject *obj) {
     return PyTruffle_SIZE(obj);
 }