Add back setsockopt path to curlx_nonblock

[donny-dont]

The implementation using setsockopt was removed when BeOS support was purged. However this functionality wasn't BeOS specific and HAVE_SETSOCKOPT_SO_NONBLOCK is still present in the codebase.

[bagder]

What is it needed for?

[donny-dont]

Found the above stopped building after the change when updating to 7.82.0.

The check for HAVE_SETSOCKOPT_SO_NONBLOCK is still in the build code, CMake and autotools, but this was the only place it was used in curl.

[bagder]

Why do you avoid to write "Orbis OS", presumably the PlayStation 4 system software? It would help if you'd mention that maybe as a comment in the code, to avoid a future mistake in the similar vein.

Does curl build fine otherwise out of the box for Orbis if this fix is brought back?

[donny-dont]

Yea so PlayStation 4/5 use cURL and this change makes it so it'll build out of the box.

[donny-dont]

Noted the bit of code is for game consoles.

[bagder]

I would still like that comment to mention more exact what OS it is for, but I can add that.

[bagder]

Thanks!

[donny-dont]

Thank you!