Allowing SYSV shared memory to allocated more than 2GB

[Matthew Dillon]

    I think it's best to bump libc and also provide compat functions
    for the syscalls that have changed.  struct ipc_perm also needs to
    be updated (ours is still using unsigned shorts for things like the
    uid).

    I'll help finish things up at the sys_/kern_ separation stage if Jan
    gets overwhelmed with the extra work.  I really want new kernels to
    be compatible w/ release kernels.  I don't want to break compatibility
    right off the bat.

						-Matt