Help needed with maintainer-mode

[Christophe Lyon <christophe.lyon@linaro.org>]

Hi!

Sorry for cross-posting, but I'm not sure the rules/guidelines are the
same in gcc vs binutils/gdb.

TL;DR: are there some guidelines about how to use/enable maintainer-mode?

In the context of the Linaro CI, I've been looking at enabling
maintainer-mode at configure time in our configurations where we test
patches before they are committed (aka "precommit CI", which relies on
patchwork).

Indeed, auto-generated files are not part of patch submissions, and
when a patch implies regenerating some files before building, we
currently report wrong failures because we don't perform such updates.

I hoped improving this would be as simple as adding
--enable-maintainer-mode when configuring, after making sure
autoconf-2.69 and automake-1.15.1 were in the PATH (using our host's
libtool and gettext seems OK).

However, doing so triggered several problems, which look like race
conditions in the build system (we build at -j160):
- random build errors in binutils / gdb with messages like "No rule to
make target 'po/BLD-POTFILES.in". I managed to reproduce something
similar manually once, I noticed an empty Makefile; the build logs are
of course difficult to read, so I couldn't figure out yet what could
cause this.

- random build failures in gcc in fixincludes. I think this is a race
condition because fixincludes is updated concurrently both from
/fixincludes and $buillddir/fixincludes. Probably fixable in gcc
Makefiles.

- I've seen other errors when building gcc like
configure.ac:25: error: possibly undefined macro: AM_ENABLE_MULTILIB
from libquadmath. I haven't investigated this yet.

I've read binutils' README-maintainer-mode, which contains a warning
about distclean, but we don't use this: we start our builds from a
scratch directory.

So... I'm wondering if there are some "official" guidelines about how
to regenerate files, and/or use maintainer-mode?  Maybe I missed a
"magic" make target (eg 'make autoreconf-all') that should be executed
after configure and before 'make all'?

I've noticed that sourceware's buildbot has a small script
"autoregen.py" which does not use the project's build system, but
rather calls aclocal/autoheader/automake/autoconf in an ad-hoc way.
Should we replicate that?

Thanks,

Christophe