Approved by: jkh

Approved by:	JKH

syscall.h and sysent.h was probably forgotten after the last change
syscalls.master.

glibc2 defines struct dirent differently than the Linux kernel does.
The getdents function therefore needs to read a heuristically defined
number of kernel dirents to satisfy the request. In case where too
many kernel dirents have been read, the function lseeks on the
directory so that a next call will start with the right dirent. The
offset used in lseeking is the offset-field in the last dirent passed
to the application. This can only mean that the offset-field holds
the offset of the next dirent and not the offset of the dirent itself.

fields in struct cdevsw:

        d_stop          moved to struct tty.
        d_reset         already unused.
        d_devtotty      linkage now provided by dev_t->si_tty.

These fields will be removed from struct cdevsw together with
d_params and d_maxio Real Soon Now.

The changes in this patch consist of:

        initialize dev->si_tty in *_open()
        initialize tty->t_stop
        remove devtotty functions
        rename ttpoll to ttypoll
        a few adjustments to these changes in the generic code
        a bump of __FreeBSD_version
        add a couple of FreeBSD tags

far-reaching in fd-land, so you'll want to consult the code for
changes.  The biggest change is that now, you don't use
	fp->f_ops->fo_foo(fp, bar)
but instead
	fo_foo(fp, bar),
which increments and decrements the fp refcount upon entry and exit.
Two new calls, fhold() and fdrop(), are provided.  Each does what it
seems like it should, and if fdrop() brings the refcount to zero, the
fd is freed as well.

Thanks to peter ("to hell with it, it looks ok to me.") for his review.
Thanks to msmith for keeping me from putting locks everywhere :)

Reviewed by:	peter

While I'm here, fix style and debug printf.

Fix derived from patch by: Darryl Okahata <darrylo@sr.hp.com>