Fix some startup-related glitches.

Fix some startup-related glitches.

src/ioset.h (ioset_update): Declare new function.

src/ioset.c (ioset_init): If we have an engine, return early.
  (ioset_add): If no engine, try to initialize.
  (ioset_update): New function.
git-archimport-id: srvx@srvx.net--2006/srvx--devo--1.3--patch-52