bpo-43269: Clean up sqlite3 file scope (GH-24578)

diff --git a/Modules/_sqlite/statement.c b/Modules/_sqlite/statement.c
index b62de58..f179eee 100644
--- a/Modules/_sqlite/statement.c
+++ b/Modules/_sqlite/statement.c
@@ -368,7 +368,8 @@ void pysqlite_statement_mark_dirty(pysqlite_Statement* self)
     self->in_use = 1;
 }
 
-void pysqlite_statement_dealloc(pysqlite_Statement* self)
+static void
+pysqlite_statement_dealloc(pysqlite_Statement *self)
 {
     PyTypeObject *tp = Py_TYPE(self);