This is simply not allowed, and doing it triggered an assertion. It's
still not allowed, because the terminal and related functionality is a
global resource, and there doesn't seem to be a sane way to manage the
signal handlers.
But be a bit nicer, and just the terminal if it's already in use.
Note that terminal _output_ happens anyway. This becomes usable with
this commit. To facilitate logging-only usage further, also explicitly
disable terminal input, so that "terminal=yes" can be used for logging
without much interference with other things. (It'll still overwrite some
signal handlers, though.)
wm4
f984b79720