bug#45085: Have so-long mode fire-sprinkler system always ready for M-x compile, M-x shell

[積丹尼 Dan Jacobson]

so-long mode is great, when opening files.
But what about the case
(compile "perl -wle 'print 8 x 888888888;'")?
That's going to produce a buffer with a really long line.
So so-long mode should jump in to the rescue.

And what about M-x shell?
If we do
$ perl -wle 'print 8 x 888888888;'
there, so-long mode should somehow 'detect there is something wrong on
the fourth floor of building H, and send in security guards to the
rescue' too.

$ grep so-long .emacs
(global-so-long-mode 1)
is what I am using here in emacs-version "27.1"

>>>> Norbert N. Nerblesome says:
> Just do M-x so-long in the buffer you are uncomfortable with, and you
> will see
> "Changed to so-long-mode (from compilation-mode).  C-c C-c to revert."
> So what's the big deal?

The big deal is, we, sadly might never have the opportunity to type
those "last words and testament," as emacs might already have gotten
locked up. Therefore one hopes the problem could be detected for us and
so-long mode activated automatically:

"Buffer has sprouted long lines. so-long mode activated to prevent emacs 
jamming itself."