• autoconf

$ wget https://ftp.gnu.org/gnu/automake/automake-1.16.3.tar.gz
$ tar xvf automake-1.16.3.tar.gz 
$ cd automake-1.16.3/
$ mkdir build
$ cd build
$ PATH=/opt/autoconf/2.69/bin:${PATH} \
  ../configure --prefix=/opt/automake/1.16.3
$ make
$ make install

$ export PATH=/opt/automake/1.16.3/bin:${PATH}