consolidate compat readv/writev/execve/select/nfsservctl [v2]

[Arnd Bergmann <arnd@arndb.de>]

I'm following up with patches to introduce new compat_sys_* functions
for the largest four ones. All of these had some bugs on most
architectures, usually resulting from missing updates after the
native handler was changed.

This is the second version of these cleanups that include a fix for
compat_sys_select and an update from Arun Sharma to use compat_do_execve
on ia64 as well.

For readv, writev, execve and select, ia64 and x86_64 use a different
method from the others and I chose to use the more common one, which
is a bit more code but avoids an extra copy of the user data.

The patches are also available at
http://www.arndb.de/patches/linux/2.6.6-rc1/ and apply cleanly
to 2.6.6-rc1 and 2.6.5-mm6. They are tested on x86_64, ia64 and s390.

Please consider for 2.6.6-rc*-mm* and 2.6.7.

	Arnd <><