message: trying to fix unimplemented flock under linux
diff: @@ -276,6 +276,9 @@ fn acquire(config: &Config,
  #[cfg(target_os = "macos")]
  Err(ref e) if e.raw_os_error() == Some(libc::ENOTSUP) => return Ok(()),
  + #[cfg(target_os = "linux")]
  + Err(ref e) if e.raw_os_error() == Some(libc::ENOSYS) => return Ok(()),
  +
  Err(e) => {
  if e.raw_os_error() != lock_contended_error().raw_os_error() {
  return Err(human(e)).chain_error(|| {
  