diff --git a/src/os/user/getgrouplist_darwin.go b/src/os/user/getgrouplist_darwin.go
index 935c6de942..e8fe26c47f 100644
--- a/src/os/user/getgrouplist_darwin.go
+++ b/src/os/user/getgrouplist_darwin.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build cgo,!osusergo
+
 package user
 
 /*