prevent direct usage of PyWrapperDescrObject struct when not building in CPython

--HG--
extra : rebase_source : 1ada6cc5efa5fa3100aa0be920245afe0b37c163

Cython/Compiler/ModuleNode.py

@@ -2208,6 +2208,7 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                 # a significant performance hit. (See trac #561.)
                 for func in entry.type.scope.pyfunc_entries:
                     if func.is_special and Options.docstrings and func.wrapperbase_cname:
+                        code.putln('#if CYTHON_COMPILING_IN_CPYTHON')
                         code.putln("{")
                         code.putln(
                             'PyObject *wrapper = __Pyx_GetAttrString((PyObject *)&%s, "%s"); %s' % (
@@ -2226,6 +2227,7 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                                 func.wrapperbase_cname))
                         code.putln("}")
                         code.putln("}")
+                        code.putln('#endif')
                 if type.vtable_cname:
                     code.putln(
                         "if (__Pyx_SetVtable(%s.tp_dict, %s) < 0) %s" % (

Cython/Compiler/Nodes.py

@@ -3429,8 +3429,10 @@ class DefNodeWrapper(FuncDefNode):
                     split_string_literal(escape_byte_string(docstr))))
 
             if entry.is_special:
+                code.putln('#if CYTHON_COMPILING_IN_CPYTHON')
                 code.putln(
                     "struct wrapperbase %s;" % entry.wrapperbase_cname)
+                code.putln('#endif')
 
         if with_pymethdef or self.target.fused_py_func:
             code.put(