Bug#978850: libidn2: ftbfs with autoconf 2.70

[Matthias Klose]

Package: src:libidn2
Version: 2.3.0-1
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/libidn2_2.3.0-1_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_USER=user42
SHELL=/bin/sh
USER=user42

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

Command: dpkg-buildpackage -us -uc -sa -rfakeroot
dpkg-buildpackage: info: source package libidn2
dpkg-buildpackage: info: source version 2.3.0-1
dpkg-buildpackage: info: source distribution unstable
dpkg-buildpackage: info: source changed by Ondřej Surý <ondrej@debian.org>
 dpkg-source --before-build .
dpkg-buildpackage: info: host architecture amd64
dpkg-source: info: using options from libidn2-2.3.0/debian/source/options: 
--diff-ignore=.git|doc/reference/tmpl/idn2.sgml|doc/reference/tmpl/idna.sgml|doc/idn2.1
 fakeroot debian/rules clean
dh clean -O--dbgsym-migration="libidn2-0-dbg (<< 2.0.2-1~)" -X.la
   dh_testdir "-O-O--dbgsym-migration=libidn2-0-dbg (<< 2.0.2-1~)" -O-X.la
   debian/rules override_dh_auto_clean
make[1]: Entering directory '/<<PKGBUILDDIR>>'
test ! -f Makefile || dh_auto_clean
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
   dh_autoreconf_clean "-O-O--dbgsym-migration=libidn2-0-dbg (<< 2.0.2-1~)" 
-O-X.la
   dh_clean "-O-O--dbgsym-migration=libidn2-0-dbg (<< 2.0.2-1~)" -O-X.la
 dpkg-source -b .
dpkg-source: warning: upstream signing key but no upstream tarball signature
dpkg-source: info: using options from libidn2-2.3.0/debian/source/options: 
--diff-ignore=.git|doc/reference/tmpl/idn2.sgml|doc/reference/tmpl/idna.sgml|doc/idn2.1
dpkg-source: info: using source format '3.0 (quilt)'
dpkg-source: info: building libidn2 using existing ./libidn2_2.3.0.orig.tar.gz
dpkg-source: info: building libidn2 in libidn2_2.3.0-1.debian.tar.xz
dpkg-source: info: building libidn2 in libidn2_2.3.0-1.dsc
 debian/rules build
dh build -O--dbgsym-migration="libidn2-0-dbg (<< 2.0.2-1~)" -X.la
   dh_testdir "-O-O--dbgsym-migration=libidn2-0-dbg (<< 2.0.2-1~)" -O-X.la
   dh_update_autotools_config "-O-O--dbgsym-migration=libidn2-0-dbg (<< 
2.0.2-1~)" -O-X.la
   debian/rules override_dh_autoreconf
make[1]: Entering directory '/<<PKGBUILDDIR>>'
gtkdocize --copy --flavour no-tmpl
find . -name Makefile.in -delete
rm -f doc/idn2.1
dh_autoreconf
Copying file config.rpath
Copying file m4/extern-inline.m4
Copying file m4/fcntl-o.m4
Copying file m4/glibc2.m4
Copying file m4/glibc21.m4
Copying file m4/intdiv0.m4
Copying file m4/intl.m4
Copying file m4/intldir.m4
Copying file m4/intmax.m4
Copying file m4/inttypes-pri.m4
Copying file m4/inttypes_h.m4
Copying file m4/lcmessage.m4
Copying file m4/lock.m4
Copying file m4/printf-posix.m4
Copying file m4/size_max.m4
Copying file m4/stdint_h.m4
Copying file m4/threadlib.m4
Copying file m4/uintmax_t.m4
Copying file m4/xsize.m4
Copying file po/Makevars.template
/usr/bin/m4:configure.ac:16: Warning: excess arguments to builtin `m4_define' 
ignored
autom4te: error: /usr/bin/m4 failed with exit status: 1
aclocal: error: echo failed with exit status: 1
autoreconf: error: aclocal failed with exit status: 1
dh_autoreconf: error: autoreconf -f -i returned exit code 1
make[1]: *** [debian/rules:14: override_dh_autoreconf] Error 25
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:7: build] Error 2
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2