RunningInUserNS detects whether we are currently running in a user namespace. Originally copied from github.com/lxc/lxd/shared/util.go
var RunningInUserNS = runningInUserNS
func GetUserNamespaceMappings(nsPath string) (uidMap, gidMap []configs.IDMap, err error)
func IsSameMapping(a, b []configs.IDMap) bool
IsSameMapping returns whether or not the two id mappings are the same. Note that if the order of the mappings is different, or a mapping has been split, the mappings will be considered different.