4.99.50 - goodbye VOP_LEASE
vn_setrecurse: if no lock is exported, use v_lock. Works around issue
described in PR kern/37808. The ideal solution here is to kill vnode
lock recursion, which should not be hard once it is understood what
the two remaining callers of vn_setrecurse() are doing.
Since VOP_LEASE is gone, remove genfs_lease_check() too.  Now my kernel
builds again.  :)
Spec_open(): clear sd_bdevvp if bdev_open() failed.

Ok: Andrew Doran <ad@netbsd.org>
vrelel: remove a bogus KASSERT.
Simplify the calibration code a great bit by just waiting around 100ms
polling the i8254 as reference and counting the cycles with that.
Disable interrupts. This should be relatively stable even in the light
of SMIs as long as they happen in the middle of the loop. This fixes
long delays during boot.

If greater precision for the calibration is desired, a second run should
be done at a different time when the HPET or ACPI timer is present. Both
provide much faster access (less jitter) and a higher frequency.
Fix dependencies on assym.h.
Some indentation for a few printfs that weren't respecting 80 chars
per line.
- Prevent LOCKDEBUG from complaining if we do rw_tryenter() on a lock
  that we already own.
- Add an assembly stub for rw_tryenter().
PR/37863: Wolfgang Stukenbrock: yp_passwd command may destroy NIS database entries when used on a server that includes users via netgroups
minor lint
Add assym.h dependencies.
PR/37864: Wolfgang Stukenbrock: when requesting TCP rcp-service port numbers
UDP is used
wait for 15 seconds, not 15 microseconds.
PR/37865: Wolfgang Stukenbrock: yppoll uses only UDP to request the map-info
Add some assym.h dependencies.
Fix fallout from v_specinfo removal.  hp300 builds again.
- Make new vnode construction MPSAFE.
- Replace use of lockmgr().
lockmgr() not used here, remove ref to it.
Note Portege 3440 support, and change working for X11 switching bug, from
Martin S. Weber on current-users.