Do not KASSERT an unsigned value being >= 0 after decrementing it; instead,
KASSERT it being > 0 before decrementing.
ok dlg@
fix remote fwding with same listen port but different listen address
with gerhard@, ok djm@
Update list of .S depencies over assym.h.
Move to a smaller rbytes buffer and skip a random part. Not to
improve the random stream itself (it doesn't), but to introduce
noise in the arc4random calling pattern. Thanks to matthew@ who
pointed out bias in a previous diff, ok deraadt@ matthew@
Standardize xfer byte counts to ssize_t rather than a mix of size_t and int
(we need to make them signed to spot controller overruns), and fix format
strings accordingly.

While there, make sure every runtime printf is prefixed by either the complete
target information, if available, or at least the driver name with the
proper instance number - supported systems with > 1 wdsc are quite common.
extra evil spaces snuck in over the last while