Re: Can't build previous versions of Emacs?

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: raman@google.com,  emacs-devel@gnu.org
> Date: Sun, 17 Jul 2022 08:49:45 +0800
> 
> Karl Berry <karl@freefriends.org> writes:
> 
> > FWIW, I was able to compile e21 on a current x86_64 machine running 
> > Alma Linux 8 (I doubt the os matters much) with the attached.
> > Copied in m/amdx86-64.h from 22.3 as a starting point. I didn't try to
> > include X support, since I had no interest in it.
> 
> Nice.  I was able to build Emacs 19.34 on a modern Fedora system.  I
> wrote some new machine files based on the existing Alpha support, but
> just that unfortunately did not quite work, since it made assumptions
> about the DEC Alpha calling convention.  So most of the work ended up
> being writing prototypes for the many implicitly declared functions,
> since returning int simply doesn't work (unlike on the Alpha.)

My hats off to MS-Windows, whose libc stability and backward
compatibility allow me to run and debug _today_ all the original
binaries of Emacs from 21.4 all the way to 28.1, each binary as it was
built in its own time.  "Modern" systems have a lesson to learn there.