diff --git a/src/cmd/go/testdata/script/cgo_lto_issue43830.txt b/src/cmd/go/testdata/script/cgo_lto_issue43830.txt
index 06ab2f34c9d..8bc7d8a540f 100644
--- a/src/cmd/go/testdata/script/cgo_lto_issue43830.txt
+++ b/src/cmd/go/testdata/script/cgo_lto_issue43830.txt
@@ -15,6 +15,7 @@ go build main.go add.go
 package main
 
 /*
+extern int myadd(int, int);
 int c_add(int a, int b) {
 	return myadd(a, b);
 }