autoreconf

Autoreconf is a utility in the GNU Autotools build system that automates the regeneration of configuration scripts and related files after changes to the Autotools inputs, such as configure.ac and Makefile.am. By orchestrating a sequence of tools, autoreconf helps ensure that the project's configure script and auxiliary files reflect the current build definitions and macro libraries, maintaining portability across environments.

When run, autoreconf typically executes aclocal to collect macro definitions from the installed macros and the project's m4 directory, autoconf to produce a new configure script from configure.ac, and autoheader to refresh config.h.in as needed. It may also invoke libtoolize (or glibtoolize on some platforms) to install or synchronize libtool support, and automake to generate Makefile.in from Makefile.am. The -i option installs missing support files such as configure, config.sub, config.guess, install-sh, and missing. The -f option forces regeneration even if a configure script already exists. Projects may customize the sequence, but the goal remains the same: refresh the Autotools bootstrap.

Autoreconf is commonly used by developers and package maintainers when modifying Autotools inputs or upgrading the autotools suite. It is not typically required for end users building a released tarball, which usually includes a pre-generated configure script produced during release preparation.

See also: Autoconf, Autoheader, Automake, Libtool, Aclocal.