MFC r258132:
Some minor tuning to rpc/svc.c:
 - close cosmetic race in svc_exit();
 - do not set wait timeout for idle threads if we have no use for wakeups;
 - create new requested thread sooner, not only after some another thread
wakeup, that may happen later under constant load.
MFC r258578, r258580, r258581 (by hrs):
Replace Sun RPC license in TI-RPC library with a 3-clause BSD license
with the explicit permissions.