operation of each clist. Limit the growth of each clist. Clists
can only grow larger than the reserved minimum if there are free
cblocks in a shared pool. The size of this pool is now fixed
(this could be improved). The reserved and maximum sizes are more
carefully allocated for slip and ppp, depending on the mtu. A maximum
MTU of 16384 is now enforced for ppp.
a clist return with an error. There are some clist starvation/deadlock
bugs elsewhere and killing clist hogs didn't help because the breaks
only exited from the inner loops.
a tty.
Note that this might conflict with the collateral use of TS_WOPEN, but
for the moment I can find no problems associated with this. (TS_WOPEN
will likely go away in the future anyway). This should be looked at
again in the future (the potential problem is that the cblock pool
may either run out or accumulate too many cblocks).