diff --git a/windows/env_unset.go b/windows/env_unset.go
deleted file mode 100644
index b712c660..00000000
--- a/windows/env_unset.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright 2014 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.
-
-// +build windows
-// +build go1.4
-
-package windows
-
-import "syscall"
-
-func Unsetenv(key string) error {
-	// This was added in Go 1.4.
-	return syscall.Unsetenv(key)
-}
diff --git a/windows/env_windows.go b/windows/env_windows.go
index e8292386..bdc71e24 100644
--- a/windows/env_windows.go
+++ b/windows/env_windows.go
@@ -23,3 +23,7 @@ func Clearenv() {
 func Environ() []string {
 	return syscall.Environ()
 }
+
+func Unsetenv(key string) error {
+	return syscall.Unsetenv(key)
+}