linux COMPAT_43 removal part 4

["David P. Reese, Jr." <daver@xxxxxxxxxxxx>]

Here are the last changes to emulation/linux/linux_socket.c.  This patch
removes COMPAT_43 completely, removes the last stackgap allocation, and
changes the last unmodified syscalls (socket() and shutdown()) so that
they use the split syscalls.

The sendfile() syscall is not included in this patch because I don't have
anything robust to test it against.  If anyone can suggest a linux binary,
I may be able to find some time to implement it properly.

I'm out of town this weekend, so I probably won't commit this until sunday
night.

-- 
   David P. Reese, Jr.                                     daver@xxxxxxxxxxxx
                                               http://www.gomerbud.com/daver/