diff --git a/test/sigchld.go b/test/sigchld.go
index 9024f39956..a60d28deaa 100644
--- a/test/sigchld.go
+++ b/test/sigchld.go
@@ -1,4 +1,4 @@
-// +build !windows !plan9
+// +build !windows
 // cmpout
 
 // Copyright 2009 The Go Authors. All rights reserved.