bug#69598: 29.2; colour support based on $TERM value not terminfo database

[Eli Zaretskii]

> From: chohag@jtan.com
> cc: chohag@jtan.com, 69598@debbugs.gnu.org
> Comments: In-reply-to Eli Zaretskii <eliz@gnu.org>
>    message dated "Fri, 08 Mar 2024 17:09:51 +0200."
> Date: Fri, 08 Mar 2024 18:52:28 +0000
> 
> > So you now agree with me that a terminal file in lisp/term is needed
> > for this situation?  Or are there issues that are still unaccounted
> > for, as far as color support is concerned?
> 
> I don't agree.

In that case, we will have to agree to disagree, sorry.

> In short, if emacs only supports colour (or any other feature) on
> specific terminals it knows about in advance, it should say so and
> not imply that a terminfo or termcap capability is sufficient.

Support for colors beyond the basic 8 is very specific to terminals.
Emacs solves this problem by relying on the name of the terminal.  So
any new terminal has to abide by this protocol.  That's how this stuff
works in Emacs.