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.

This port is specifically designed for developers that want to create
cross-platform software distributions on FreeBSD.  This version of autoconf
should _NEVER_ be used with the FreeBSD ports system as a replacement for the
versioned copies of autoconf.

WWW: http://www.gnu.org/software/autoconf/