new struct statfs changed committed

["Todd C. Miller" <Todd_(_dot_)_Miller_(_at_)_courtesan_(_dot_)_com>]

[ This applies to version 1.29 of src/sys/sys/mount.h -- anoncvs mirrors
  may not yet be up to date. ]

The short story:
    You must build and boot a new kernel before running a "make build"
    or the build will fail with "unimplemented system call" errors.

The long story:
    I just committed new statfs(2), fstatfs(2), and getfsstat(2)
    system calls that use a new "struct statfs".  Details follow.

The new struct statfs has the following featuires
    1) Has a u_int32_t flags field--now softdep can have a real flag.
    2) Uses u_int32_t instead of longs (nicer on the alpha).
       Note: the man page used to lie about setting invalid/unused
	     fields to -1.  SunOS does that but our code never has.
    3) Gets rid of f_type completely.  It hasn't been used since NetBSD 0.9
       and having it there but always 0 is confusing.  It is conceivable
       that this may cause some old code to not compile but that is better
       than silently breaking.
    4) Adds a mount_info union that contains the FSTYPE_args struct
       (inspired by Digital UNIX).  This means that "mount" can now
       tell you all the options a filesystem was mounted with.
       This is especially nice for NFS.

Other changes:
    1) The linux statfs emulation didn't convert between BSD fs names
       and linux f_type numbers.  Now it does, since the BSD f_type
       number is useless to linux apps ;-)
    2) FreeBSD's struct statfs is different from our (both old and new)
       and thus needed conversion.  Previously, the OpenBSD syscalls
       were used without any real translation.

The cool part:
mount(8) has been modified to use mount_info for filesystems with *_args
structs.  Previously, mount with no args would print:
    xerxes:/home/cvs on /cvs type nfs

Now, it prints:
    xerxes:/home/cvs on /cvs type nfs (v3, tcp)

And "mount -v" shows:
    xerxes:/home/cvs on /cvs type nfs (rw, v3, hard, tcp, wsize=8192, \
	rsize=8192, rdirsizerdirsize=8192, timeo=10, retrans=10, \
	maxgrouplist=16, readahead=1)

In non-verbose mode mount only prints things that differ from the defaults.
Also, mount_nfs has been fixed such that NFSV3 mounts now use TCP by
default, like other OS's do.