Re: Found some old GNU Make patches of mine.

[Eli Zaretskii]

> Date: Thu, 20 Apr 2023 06:29:11 -0700
> From: Kaz Kylheku <729-670-0061@kylheku.com>
> 
> I found a large Subversion repository of code that I thought
> had been lost for 13 years, from a startup that folded in 2010. 
> 
> It includes the changes I made to GNU Make 3.80 to make it
> dump executable images after parsing the makefiles.
> I'm sure I wrote about this before.
> 
> The time stamps are spaced close together because I was
> likely converting a quilt patch stack into commits:
> 
> ~/svn/customized-tools/make$ svn log
> ------------------------------------------------------------------------
> r531 | kaz | 2007-01-15 14:43:03 -0800 (Mon, 15 Jan 2007) | 7 lines 
> 
> Change-ID: use-unexec 
> 
> Add --dump-image option to save an image and quit after loading the goal 
> chain.
> Some tricky things had to be done to make the restarting work, like
> reallocating the argument vector into malloced memory, and disabling the use
> of mmap for memory allocation. 
> 
> ------------------------------------------------------------------------
> r530 | kaz | 2007-01-15 14:31:00 -0800 (Mon, 15 Jan 2007) | 4 lines 
> 
> Change-ID: compile-unexec 
> 
> Modify unexec stuff for integration with make. 
> 
> ------------------------------------------------------------------------
> r529 | kaz | 2007-01-15 14:29:51 -0800 (Mon, 15 Jan 2007) | 4 lines 
> 
> Change-ID: add-emacs-21.4-unexec 
> 
> Adding unexec facility to make. 

FWIW, Emacs moved away from using unexec several years ago, to a much
more portable dump/restart system.  We did that because unexec was
interacting poorly with modern systems, and in particular with their
memory-allocation routines in a typical libc.

So I won't recommend adopting unexec in GNU Make, as it goes against
the Emacs experience, for which the Emacs development team paid dearly
in blood and tears.  If we want something like this in GNU Make (and
I'm not yet sure it's really a good idea), it is better to use the
"portable dumper" technique Emacs uses since v27.1.