bug#41544: 26.3; Possible incorrect results from color-distance

[Eli Zaretskii]

> Date: Mon, 01 Jun 2020 20:35:53 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: tom@tromey.com, simon@polaris64.net, 41544@debbugs.gnu.org
> 
> I'm just looking at the changes.  I see a change in how colors are
> converted to RGB triplets.  I see a change in what colors are
> considered dark and light, with a new function which decides that that
> is being used for frame background mode and in several lisp/term/
> files, including 16-color terminals.  I'm asking why do we want to
> make all those changes, which modify very basic aspects of our color
> support on many terminals.

And then, of course, there are the changes in color-distance itself,
which change the values it returns.  Again, why such significant
changes to fix an otherwise insignificant bug?