bug#57669: 29.0.50; C-n, C-p off under long lines

[dick]

> This has NIH written all over it.

You mean GNU Emacs suffers from NIH, or Commercial Emacs?

The Commercial Emacs long lines fix *preceded* GNU's by about six months
(and I might add, did so without resorting to the blunt instrument of
narrowing).

The proposer of the GNU Emacs fix even paraphrased Commercial Emacs
when he said:

  Perfect is the enemy of good.  Emacs users have been plagued for decades
  by this bug.[1]

See [2],[3] from where his words might have found inspiration.

To be clear, I'm not aggrieved.  I just want everyone to understand that
NIH is too unmeditated an accusation.

[1] https://debbugs.gnu.org/cgi/bugreport.cgi?msg=119;bug=56393
[2] https://youtu.be/5C3wB3xiMmU?t=80
[3] https://youtu.be/5C3wB3xiMmU?t=290