New default for truncate-partial-width-windows

[Glenn Morris]

Sorry to dredge up old stuff. I don't have the original thread to
reply to, but am replying to "Display-based word wrapping", 24 Jun 2008:

http://lists.gnu.org/archive/html/emacs-devel/2008-06/msg01693.html

Chong Yidong:

>>> I have also changed truncate-partial-width-windows to accept integer
>>> values specifying a window width below which to truncate lines, and
>>> changed the default to 30.

Stefan Monnier:

>> Since the Emacs-22 default was t, I think a safer new default (other
>> than t) would be something around 70-80, so it behaves as before for
>> 80 column frames.

I just want to agree with the above comment. With an 80-column frame
(which I guess with no evidence is a fairly typical size), then

emacs -Q README
C-x 3

looks pretty poor to me, because the lines are fairly short, but don't
get truncated. It looks better in 22.2 where the lines are truncated.

Chong Yidong:

> For anyone using the word-wrap feature, that could be annoying.  With
> word wrapping, buffers with long lines can be comfortably read in
> 50-column windows, but if truncate-partial-width-windows is 70-80,
> they'll be truncated rather than wrapped.

I can't comment on that since I don't use word-wrap, but would argue
that it's more important for the default behaviour to look better and
be more consistent with 22. Is 45-50 an acceptable compromise?