Bug#978875: ocaml: ftbfs with autoconf 2.70

[Matthias Klose <doko@debian.org>]

Package: src:ocaml
Version: 4.08.1-10
Severity: normal
Tags: sid bookworm
User: doko@debian.org
Usertags: ftbfs-ac270

[This bug report is not targeted to the upcoming bullseye release]

The package fails to build in a test rebuild on at least amd64 with
autoconf 2.70, but succeeds to build with autoconf 2.69. The
severity of this report will be raised before the bookworm release,
so nothing has to be done for the bullseye release.

The full build log can be found at:
http://qa-logs.debian.net/2020/09/26.ac270/ocaml_4.08.1-10_unstable_ac270.log
The last lines of the build log are at the end of this report.

To build with autoconf 2.70, please install the autoconf package from
experimental:  apt-get -t=experimental install autoconf 

[...]
SCHROOT_ALIAS_NAME=unstable
SCHROOT_CHROOT_NAME=sid-amd64-sbuild
SCHROOT_COMMAND=env
SCHROOT_GID=1001
SCHROOT_GROUP=user42
SCHROOT_SESSION_ID=sid-amd64-sbuild-8b8d0097-0e9c-4202-831e-bd0bc30e720c
SCHROOT_UID=1001
SCHROOT_USER=user42
SHELL=/bin/sh
USER=user42

dpkg-buildpackage
-----------------

Command: dpkg-buildpackage -us -uc -sa -rfakeroot
dpkg-buildpackage: info: source package ocaml
dpkg-buildpackage: info: source version 4.08.1-10
dpkg-buildpackage: info: source distribution unstable
dpkg-buildpackage: info: source changed by Stéphane Glondu <glondu@debian.org>
 dpkg-source --before-build .
dpkg-buildpackage: info: host architecture amd64
 debian/rules clean
dh clean
   debian/rules override_dh_auto_clean
make[1]: Entering directory '/<<PKGBUILDDIR>>'
/usr/bin/make -f /<<PKGBUILDDIR>>/debian/ocamlinit.mk ocamlinit-clean
make[2]: Entering directory '/<<PKGBUILDDIR>>'
rm -f ocamlinit-stamp debian/ld.conf debian/ocaml-base-nox.postinst debian/ocaml-base-nox.prerm debian/ocaml-nox.lintian-overrides debian/ocaml-nox.manpages debian/ocaml-nox.postinst debian/ocaml-source.install
make[2]: Leaving directory '/<<PKGBUILDDIR>>'
if test -d boot.debian; then \
  rm -Rf boot; \
  mv boot.debian boot; \
fi
set -e; for ext in sub guess; do \
  if [ -f debian/config.orig.$ext ] ; then \
    mv -f debian/config.orig.$ext config/gnu/config.$ext; \
  fi; \
done
rm -Rf debian/ocaml-source-4.08.1.tar debian/test-build
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
   dh_clean
 dpkg-source -b .
dpkg-source: info: using source format '3.0 (quilt)'
dpkg-source: info: building ocaml using existing ./ocaml_4.08.1.orig.tar.xz
dpkg-source: info: using patch list from debian/patches/series
dpkg-source: info: building ocaml in ocaml_4.08.1-10.debian.tar.xz
dpkg-source: info: building ocaml in ocaml_4.08.1-10.dsc
 debian/rules binary
dh binary
   debian/rules build
make[1]: Entering directory '/<<PKGBUILDDIR>>'
dh build
   dh_update_autotools_config
   debian/rules override_dh_autoreconf
make[2]: Entering directory '/<<PKGBUILDDIR>>'
./autogen
configure.ac:1518: warning: $as_echo is obsolete; use AS_ECHO(["message"]) instead
lib/m4sugar/m4sh.m4:673: AS_IF is expanded from...
./lib/autoconf/general.m4:2149: AC_CACHE_VAL is expanded from...
./lib/autoconf/general.m4:2170: AC_CACHE_CHECK is expanded from...
build-aux/ax_pthread.m4:88: AX_PTHREAD is expanded from...
lib/m4sugar/m4sh.m4:581: AS_CASE is expanded from...
lib/m4sugar/m4sh.m4:673: AS_IF is expanded from...
configure.ac:1518: the top level
make[2]: *** [debian/rules:303: override_dh_autoreconf] Error 1
make[2]: Leaving directory '/<<PKGBUILDDIR>>'
make[1]: *** [debian/rules:82: build] Error 2
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:77: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2