Job control not working on ksh
------------------------------

Triggering:
- Only effects shell launched from login.
  Subshells exempted.
- exec'ing a new shell from the login shell, is still effected.
- Occurs even when job monitoring (`set -o monitor`) reports being on.

Demonstration:
```
perette@lenora ~ $ sleep 5 &
[1]	4467
perette@lenora ~ $ fg %1
ksh: fg: No job control
perette@lenora ~ $ sleep 5 &
[1]	26065
perette@lenora ~ [subshell 2]$ fg %1
sleep 5 
perette@lenora ~ [subshell 2]$
```

Related:
``
$ sleep 10 &
$ disown %1
ksh: disown: No job control
``

However, this works in a subshell unless job monitoring is disabled.
When monitoring is disabled, ^Z interrupts jobs but job can not be
re-enabled with %1 until a `set -o monitor` is performed.  Then it
can be done, even retroactively.

Related 2:
`set -o notify` has no effect.  Jobs always report completion between
commands, never immediately on command completion.


Notes:
misc.c contains 'bg' built-in code.
It looks for SH_MONITOR option AND job.jobcontrol

Stucture 'limits' contains variable
	posix_jobcontrol; comment indicates non-0 for job control

Structure 'process' contains variable
	'jobcontrol'; comment indicates "turned on" for real job control

Job control not being enabled by job_init.
:622 sets process group ID
:623 set fails via e-perm, and goes into
:625 tries to wait until its in foreground, skips out immediately (as expected)
:637 Warning: endif (SIGTTIN) does not match #ifdef on :621 (SIGTSTP)
:640 This block is skipped (NTTYDISC undefined on my system)
:661 possible is still false from earlier so
...and thus we never get around to enabling job control (job.jobcontrol at :692).




I don't have NTTYDISC so that whole block gets skipped, which puts us at...