[BusyBox] another hush fix

[Larry Doolittle]

Erik wrote:
> hush is now 26k, vs 19k for lash.  I am tempted to remove lash 
> all together.  There is nothing that lash does that hush does 
> not do better at this point.

To which Tom responded:
> You may want to leave it in there for those people that need only a
> _BASIC_LEVEL_ shell, and have tighter space constraints.

And then Erik came back with:
> Some carefully placed #defines in hush can also do this job.

I'm not convinced that hush should have #defines added.
While it's not spaghetti code (I've seen plenty of that)
it is relatively tightly woven, and a lot of the features
don't take up nearly as much space as the basic infrastructure.

It would make more sense to strip _lash_ down, such as getting
rid of backticks and if/then/else/fi handling, that don't really
work right anyway.  Then see if any of the bug fixes for hush,
like setpgrgp calls, can be back-ported for lash.  Lash would
end up smaller, simpler, and still usable for truly low end work.

I haven't checked, but I suspect lash handles interrupts better.
Hush probably leaks memory if you do something like
$ if true; then
> (echo foo; cat bar
> ^C
$
Hmmm.  It's worse than that.  ^C doesn't even get you back to
the "$" prompt!  You _have_ to give the "); fi" to get out.

The going rate for Flash is what, about $10/MB?  That means
hush costs about 5 cents per copy more than lash.  What's the
estimate of the unit shipments of embedded Linux next year?

       - Larry