use a dedicated macro to guard calls to _PyType_Lookup()

Cython/Utility/ExtensionTypes.c

@@ -90,13 +90,13 @@ static int __Pyx_setup_reduce(PyObject* type_obj) {
     PyObject *setstate = NULL;
     PyObject *setstate_cython = NULL;
 
-#if CYTHON_COMPILING_IN_CPYTHON
+#if CYTHON_USE_PYTYPE_LOOKUP
     if (_PyType_Lookup((PyTypeObject*)type_obj, PYIDENT("__getstate__"))) goto GOOD;
 #else
     if (PyObject_HasAttr(type_obj, PYIDENT("__getstate__"))) goto GOOD;
 #endif
 
-#if CYTHON_COMPILING_IN_CPYTHON
+#if CYTHON_USE_PYTYPE_LOOKUP
     object_reduce_ex = _PyType_Lookup(&PyBaseObject_Type, PYIDENT("__reduce_ex__")); if (!object_reduce_ex) goto BAD;
 #else
     object_reduce_ex = __Pyx_PyObject_GetAttrStr((PyObject*)&PyBaseObject_Type, PYIDENT("__reduce_ex__")); if (!object_reduce_ex) goto BAD;
@@ -105,7 +105,7 @@ static int __Pyx_setup_reduce(PyObject* type_obj) {
     reduce_ex = __Pyx_PyObject_GetAttrStr(type_obj, PYIDENT("__reduce_ex__")); if (unlikely(!reduce_ex)) goto BAD;
     if (reduce_ex == object_reduce_ex) {
 
-#if CYTHON_COMPILING_IN_CPYTHON
+#if CYTHON_USE_PYTYPE_LOOKUP
         object_reduce = _PyType_Lookup(&PyBaseObject_Type, PYIDENT("__reduce__")); if (!object_reduce) goto BAD;
 #else
         object_reduce = __Pyx_PyObject_GetAttrStr((PyObject*)&PyBaseObject_Type, PYIDENT("__reduce__")); if (!object_reduce) goto BAD;

Cython/Utility/ModuleSetupCode.c

@@ -49,6 +49,8 @@
 
   #undef CYTHON_USE_TYPE_SLOTS
   #define CYTHON_USE_TYPE_SLOTS 0
+  #undef CYTHON_USE_PYTYPE_LOOKUP
+  #define CYTHON_USE_PYTYPE_LOOKUP 0
   #undef CYTHON_USE_ASYNC_SLOTS
   #define CYTHON_USE_ASYNC_SLOTS 0
   #undef CYTHON_USE_PYLIST_INTERNALS
@@ -78,6 +80,8 @@
   #ifndef CYTHON_USE_TYPE_SLOTS
     #define CYTHON_USE_TYPE_SLOTS 1
   #endif
+  #undef CYTHON_USE_PYTYPE_LOOKUP
+  #define CYTHON_USE_PYTYPE_LOOKUP 0
   #undef CYTHON_USE_ASYNC_SLOTS
   #define CYTHON_USE_ASYNC_SLOTS 0
   #undef CYTHON_USE_PYLIST_INTERNALS
@@ -111,6 +115,13 @@
   #ifndef CYTHON_USE_TYPE_SLOTS
     #define CYTHON_USE_TYPE_SLOTS 1
   #endif
+  #if PY_VERSION_HEX < 0x02070000
+    // looks like calling _PyType_Lookup() isn't safe in Py<=2.6/3.1
+    #undef CYTHON_USE_PYTYPE_LOOKUP
+    #define CYTHON_USE_PYTYPE_LOOKUP 0
+  #elif !defined(CYTHON_USE_PYTYPE_LOOKUP)
+    #define CYTHON_USE_PYTYPE_LOOKUP 1
+  #endif
   #if PY_MAJOR_VERSION < 3
     #undef CYTHON_USE_ASYNC_SLOTS
     #define CYTHON_USE_ASYNC_SLOTS 0

Cython/Utility/ObjectHandling.c

@@ -1036,8 +1036,7 @@ static CYTHON_INLINE PyObject *__Pyx_GetAttr(PyObject *o, PyObject *n) {
 /////////////// PyObjectLookupSpecial.proto ///////////////
 //@requires: PyObjectGetAttrStr
 
-#if CYTHON_COMPILING_IN_CPYTHON && PY_VERSION_HEX >= 0x02070000
-// looks like calling _PyType_Lookup() isn't safe in Py<=2.6/3.1
+#if CYTHON_USE_PYTYPE_LOOKUP && CYTHON_USE_TYPE_SLOTS
 static CYTHON_INLINE PyObject* __Pyx_PyObject_LookupSpecial(PyObject* obj, PyObject* attr_name) {
     PyObject *res;
     PyTypeObject *tp = Py_TYPE(obj);