lib/osutil: Use unix lowprio implementation on Android (#4844)

lib/osutil/lowprio_linux.go

@@ -4,6 +4,8 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
+// +build !android
+
 package osutil
 
 import (

lib/osutil/lowprio_unix.go

@@ -4,7 +4,7 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-// +build !windows,!linux
+// +build !windows,!linux android
 
 package osutil