uv_translate_sys_error() was a private function for Windows.
This commit adds an equivalent function on other platforms, and
exposes it as public API.
Exposing this is useful in scenarios where the application uses
both libuv functions and platform-specific system calls and wants
to report errors uniformly as libuv errors.
Fixes: https://github.com/libuv/libuv/issues/79
PR-URL: https://github.com/libuv/libuv/pull/1060
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>
f1863dae6b