Define `Py_ISSPACE()` if PyPy lacks it.

Cython/Utility/ModuleSetupCode.c

@@ -784,6 +784,10 @@ static CYTHON_INLINE PyObject * __Pyx_PyDict_GetItemStrWithError(PyObject *dict,
   #define PyObject_Format(obj, fmt)  PyObject_CallMethod(obj, "__format__", "O", fmt)
 #endif
 
+#if CYTHON_COMPILING_IN_PYPY && !defined(Py_ISSPACE)
+  #define Py_ISSPACE(c)  Py_UNICODE_ISSPACE(c)
+#endif
+
 // ("..." % x)  must call PyNumber_Remainder() if x is a string subclass that implements "__rmod__()".
 #define __Pyx_PyString_FormatSafe(a, b)   ((unlikely((a) == Py_None || (PyString_Check(b) && !PyString_CheckExact(b)))) ? PyNumber_Remainder(a, b) : __Pyx_PyString_Format(a, b))
 #define __Pyx_PyUnicode_FormatSafe(a, b)  ((unlikely((a) == Py_None || (PyUnicode_Check(b) && !PyUnicode_CheckExact(b)))) ? PyNumber_Remainder(a, b) : PyUnicode_Format(a, b))