Re: [RFC] add regenerate Makefile target

[Eric Gallager <egall@gwmail.gwu.edu>]

On Tue, Mar 19, 2024 at 2:10 PM Tom Tromey <tom@tromey.com> wrote:
>
> > not sure if the current autoregen.py is in sync with that?
>
> I'm curious why "autoreconf -f" is insufficient.
> It seems to me that this should work.

`autoreconf -f` works fine in individual subdirectories, the problem
is that the top-level configure.ac doesn't use the AC_CONFIG_SUBDIRS
macro to specify its subdirectories, but rather uses its own
hand-rolled method of specifying subdirectories that autoreconf
doesn't know about. This means that autoreconf won't automatically
recurse into all the necessary subdirectories by itself automatically,
and instead has to be run manually in each subdirectory separately.
Also the various subdirectories are inconsistent about whether they
have a rule for running it (autoreconf) from the Makefile or not,
which usually comes down to whether the subdirectory uses automake for
its Makefile or not (the top-level Makefile doesn't; it uses its own
weird autogen-based regeneration method instead, which means that it
misses out on all the built-in rules that automake would implicitly
generate, including ones related to build system regeneration).

>
> > Also... I discovered the existence of an automake rule:
> > am--refresh which IIUC is intended to automake the update of Makefile
> > and its dependencies.
>
> Don't use that rule directly.  It's an implementation detail and
> shouldn't be relied on.
>
> thanks,
> Tom