avoid using PyDict_GetItemWithError in pypy3 (missing in its cpyext emulation)

Cython/Utility/ObjectHandling.c

@@ -225,7 +225,7 @@ static CYTHON_INLINE int __Pyx_IterFinish(void) {
 
 /////////////// DictGetItem.proto ///////////////
 
-#if PY_MAJOR_VERSION >= 3
+#if PY_MAJOR_VERSION >= 3 && !CYTHON_COMPILING_IN_PYPY
 static PyObject *__Pyx_PyDict_GetItem(PyObject *d, PyObject* key) {
     PyObject *value;
     value = PyDict_GetItemWithError(d, key);

Cython/Utility/Optimize.c

@@ -161,7 +161,7 @@ static PyObject* __Pyx_PyDict_GetItemDefault(PyObject* d, PyObject* key, PyObjec
 
 static PyObject* __Pyx_PyDict_GetItemDefault(PyObject* d, PyObject* key, PyObject* default_value) {
     PyObject* value;
-#if PY_MAJOR_VERSION >= 3
+#if PY_MAJOR_VERSION >= 3 && !CYTHON_COMPILING_IN_PYPY
     value = PyDict_GetItemWithError(d, key);
     if (unlikely(!value)) {
         if (unlikely(PyErr_Occurred()))
@@ -207,7 +207,7 @@ static CYTHON_INLINE PyObject *__Pyx_PyDict_SetDefault(PyObject *d, PyObject *ke
 #else
     if (is_safe_type == 1 || (is_safe_type == -1 &&
         /* the following builtins presumably have repeatably safe and fast hash functions */
-#if PY_MAJOR_VERSION >= 3
+#if PY_MAJOR_VERSION >= 3 && !CYTHON_COMPILING_IN_PYPY
             (PyUnicode_CheckExact(key) || PyString_CheckExact(key) || PyLong_CheckExact(key)))) {
         value = PyDict_GetItemWithError(d, key);
         if (unlikely(!value)) {