diff --git a/src/os/file_darwin.go b/src/runtime/cgo/tmpdir_darwin.go
similarity index 98%
rename from src/os/file_darwin.go
rename to src/runtime/cgo/tmpdir_darwin.go
index ee3a954683..1239c70de9 100644
--- a/src/os/file_darwin.go
+++ b/src/runtime/cgo/tmpdir_darwin.go
@@ -4,7 +4,7 @@
 
 // +build arm arm64
 
-package os
+package cgo
 
 /*
 #cgo CFLAGS: -x objective-c