libuv libuv asynchronous I/O Library

Most features of libuv are supported by current port, except SIGPROF relative function (loop_configure).

Nearly full libuv’s test suite available on NuttX, but some known case can’t run on sim:

• loop_update_time

• idle_starvation

• signal_multiple_loops

• signal_pending_on_close

• metrics_idle_time

• metrics_idle_time_thread

• metrics_idle_time_zero

And some will cause crash by some reason:

• fs_poll_ref