message: Ignore ENOTSUP in file locking on Linux too
  Apparently there are some filesystems that return this!
  Closes
diff: @@ -271,10 +271,11 @@ fn acquire(config: &Config,
  match try() {
  Ok(()) => return Ok(()),
  - // Like above, where we ignore file locking on NFS mounts on Linux, we
  - // do the same on OSX here. Note that ENOTSUP is an OSX_specific
  - // constant.
  - #[cfg(target_os = "macos")]
  + // In addition to ignoring NFS which is commonly not working we also
  + // just ignore locking on filesystems that look like they don't
  + // implement file locking. We detect that here via the return value of
  + // locking (e.g. inspecting errno).
  + #[cfg(unix)]
  Err(ref e) if e.raw_os_error() == Some(libc::ENOTSUP) => return Ok(()),
  #[cfg(target_os = "linux")]
  