Fix FunctionState handling for module cleanup function.

Cython/Compiler/ModuleNode.py

@@ -2658,6 +2658,8 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
 
         code.putln('static void %s(CYTHON_UNUSED PyObject *self) {' %
                    Naming.cleanup_cname)
+        code.enter_cfunc_scope(env)
+
         if Options.generate_cleanup_code >= 2:
             code.putln("/*--- Global cleanup code ---*/")
             rev_entries = list(env.var_entries)