[Rsbackup-maint] Bug#908644: rsbackup FTBFS with automake 1.16

[Adrian Bunk]

Source: rsbackup
Version: 5.0-2
Severity: serious
Tags: ftbfs

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/rsbackup.html

...
/usr/bin/make
make[1]: Entering directory '/build/1st/rsbackup-5.0'
CDPATH="${ZSH_VERSION+.}:" && cd . && /bin/bash /build/1st/rsbackup-5.0/config.aux/missing aclocal-1.15 
/build/1st/rsbackup-5.0/config.aux/missing: line 81: aclocal-1.15: command not found
WARNING: 'aclocal-1.15' is missing on your system.
         You should only need it if you modified 'acinclude.m4' or
         'configure.ac' or m4 files included by 'configure.ac'.
         The 'aclocal' program is part of the GNU Automake package:
         <http://www.gnu.org/software/automake>
         It also requires GNU Autoconf, GNU m4 and Perl in order to run:
         <http://www.gnu.org/software/autoconf>
         <http://www.gnu.org/software/m4/>
         <http://www.perl.org/>
make[1]: *** [Makefile:394: aclocal.m4] Error 127