Adapt cycplass code to breaking changes in C API

Since Python 3.9a4 , Py_REFCNT and Py_TYPE should no longer be used to
assign a value. Instead, Py_SET_REFCNT and Py_SET_TYPE should be used.

Since Python 3.10, Py_REFCNT can no longer be used to assign a value
at all.

See https://bugs.python.org/issue39573

Cython/Compiler/ModuleNode.py

@@ -1394,8 +1394,8 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
         objstruct_cname = wrapper_type.objstruct_cname
         code.putln("if (self) {")
         code.putln("%s * wrapper = (%s *) self;" % (objstruct_cname, objstruct_cname))
-        code.putln("Py_REFCNT(wrapper) = 0;")
-        code.putln("Py_TYPE(wrapper) = %s;" % wrapper_type.typeptr_cname)
+        code.putln("__Pyx_SET_REFCNT(wrapper, 0);")
+        code.putln("__Pyx_SET_TYPE(wrapper, %s);" % wrapper_type.typeptr_cname)
         code.putln("}")
 
     def generate_typedef(self, entry, code):