diff --git a/src/syscall/export_darwin_test.go b/src/syscall/export_darwin_test.go
new file mode 100644
index 00000000000..40d18f9144b
--- /dev/null
+++ b/src/syscall/export_darwin_test.go
@@ -0,0 +1,13 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package syscall
+
+func Ioctl(fd, req, arg uintptr) Errno {
+	err := ioctl(int(fd), int(req), int(arg))
+	if err != nil {
+		return err.(Errno)
+	}
+	return 0
+}
diff --git a/src/syscall/export_unix_test.go b/src/syscall/export_unix_test.go
index b41fe2f86b3..4c3d0f6d2ad 100644
--- a/src/syscall/export_unix_test.go
+++ b/src/syscall/export_unix_test.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin dragonfly freebsd linux netbsd openbsd
+// +build dragonfly freebsd linux netbsd openbsd
 
 package syscall