Implement suport for remote POSIX locks
The C implementation of the daemon has limited support for remote POSIX locks, restricted exclusively to non-blocking operations. We tried to implement the same level of functionality in #2 (closed), but we finally decided against it because, in practice most applications will fail if non-blocking operations aren't supported.
Implementing support for non-blocking isn't trivial and will probably require extending the kernel interface before we can even start working on the daemon side.