Autoconf is an extensible package of M4 macros that produce shell scripts to automatically configure software source code packages. These scripts can adapt the packages to many kinds of UNIX-like systems without manual user intervention. Autoconf creates a configuration script for a package from a template file that lists the operating system features that the package can use, in the form of M4 macro calls. http://www.gnu.org/software/autoconf/
See http://ftp.gnu.org/gnu/autoconf/ for releases.
Edit the Makefile to ensure that you are setting the intended version, then run make.
make