diff --git a/src/runtime/testdata/testwinlibsignal/dummy.go b/src/runtime/testdata/testwinlibsignal/dummy.go
index 82dfd91c93..e610f15d06 100644
--- a/src/runtime/testdata/testwinlibsignal/dummy.go
+++ b/src/runtime/testdata/testwinlibsignal/dummy.go
@@ -1,7 +1,10 @@
+//go:build windows
 // +build windows
 
 package main
 
+import "C"
+
 //export Dummy
 func Dummy() int {
 	return 42