diff --git a/Python/ast.c b/Python/ast.c
index 146cd05..5426c02 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -203,7 +203,8 @@
         c.c_encoding = STR(n);
         n = CHILD(n, 0);
     } else {
-        c.c_encoding = NULL;
+	/* PEP 3120 */
+        c.c_encoding = "utf-8";
     }
     c.c_arena = arena;