Make _executor() and _destructor() static.

theano/gof/cc.py

@@ -1287,22 +1287,22 @@ class CLinker(link.Linker):
         # instantiate.
         if PY3:
             static = """
-        int {struct_name}_executor({struct_name} *self) {{
+        static int {struct_name}_executor({struct_name} *self) {{
             return self->run();
         }}
 
-        void {struct_name}_destructor(PyObject *capsule) {{
+        static void {struct_name}_destructor(PyObject *capsule) {{
             {struct_name} *self = ({struct_name} *)PyCapsule_GetContext(capsule);
             delete self;
         }}
         """.format(struct_name=self.struct_name)
         else:
             static = """
-        int %(struct_name)s_executor(%(struct_name)s* self) {
+        static int %(struct_name)s_executor(%(struct_name)s* self) {
             return self->run();
         }
 
-        void %(struct_name)s_destructor(void* executor, void* self) {
+        static void %(struct_name)s_destructor(void* executor, void* self) {
             delete ((%(struct_name)s*)self);
         }
         """ % dict(struct_name=self.struct_name)