SOC_U: Implemented some socket functions

This allows ftpony and ftbrony to work.
It's using Berkeley sockets directly since that's what the soc:U service exposes to applications.
I'm not doubting that some/most compilers do this correctly. I wonder to what extent it is within the specification though. Apparently MSDN talks about the term "natural alignment", but doesn't make it clear whether it is part of the standard or just compiler-specific :/