There are programs, e.g. curl, that check if a connection was
established successfully by looking at SO_ERROR. Pretend that
the getsockopt() call was executed to keep them happy. If they
try to use a broken connection, the other socket functions will
bail.
If 'close' does not call 'unlink' like 'shutdown', the Lxip_socket_dir
never gets destroyed and thus the socket server leaks resources like
RAM and ports.
Ref #2285
Our 'shutdown' implementation handles only the case that 'how' is 'RDWR'.
Thus, print an error and continue if a user calls it with another value.
Fixes#2285
The socket file system can be configured in the "socket" attribute of
the libc config node like follows.
<vfs> <dir name="socket"> <fs/> </dir> </vfs>
<libc ... socket="/socket"/>
This configures the socket file system libc backend to access files in
"/socket" for socket operations.
