Without the fix build on automake-1.16.5 fails as:
configure.ac:34: error: AM_INIT_AUTOMAKE expanded multiple times
.../automake-1.16.5/share/aclocal-1.16/init.m4:29: AM_INIT_AUTOMAKE is expanded from...
configure.ac:19: the top level
.../automake-1.16.5/share/aclocal-1.16/init.m4:29: AM_INIT_AUTOMAKE is expanded from...
configure.ac:34: the top level