diff --git a/m4/d-type.m4 b/m4/d-type.m4
index 3ab69b444..bf94903fc 100644
--- a/m4/d-type.m4
+++ b/m4/d-type.m4
@@ -1,4 +1,4 @@
-#serial 2
+#serial 3
 
 dnl From Jim Meyering.
 dnl