[usocket-devel] better SOCKET-CONNECT for SBCL

Current implementation has the following defects: * The socket stream ends up with a bogus name as it is created before the socket is connected, making things harder to debug than they need to be. * In case of error, SB-BSD-SOCKETS:SOCKET-CLOSE was not being called with :ABORT T. * A unwind from SOCKET-CONNECT that didn't go through the handler leaked an FD. * An innocent non-error SIGNAL for any reason during SOCKET-CONNECT was taken to be a fatal error due to the handler on type T. * On datagram sockets CONNECTED-P wasn't set. Attached patch addresses these issues. Not deeply tested, though. Cheers, -- Nikodemus