bug#9106: 24.0.50; ./configure causes massive recompilation

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> Invocation of the `configure' script causes recompilation of many
> source files, even though nothing has really changed.
>
> It looks like the cause is lib/Makefile which states that several
> generated headers in that directory depend on config.status.  So each
> `configure' causes those headers to be regenerated, which in turn
> triggers many files using those headers to be recompiled.
>
> This is annoying, as building Emacs even on a modern system takes a
> significant amount of time (about 3 minutes on this box, whose details
> see below).  Can this annoyance be removed, please?

Reading this bug thread, it seems that various options were suggested
(mostly around different move-if-changed solutions), but they all seemed
to have various problems.

I think that it's unlikely that a user runs configure twice in a row
without changing any options, so I don't personally see any problems
with re-compiling all the .c files after running configure, so I wonder
whether there's really anything to be done here.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no