The GNU Autoconf Archive is a collection of more than 500 macros for
GNU Autoconf that have been contributed as free software by friendly
supporters of the cause from all over the Internet. Every single one of
those macros can be re-used without imposing any restrictions whatsoever
on the licensing of the generated configure script. In particular, it is
possible to use all those macros in configure scripts that are meant for
non-free software. This policy is unusual for a Free Software Foundation
project. The FSF firmly believes that software ought to be free, and
software licenses like the GPL are specifically designed to ensure that
derivative work based on free software must be free as well. In case of
Autoconf, however, an exception has been made, because Autoconf is at
such a pivotal position in the software development tool chain that the
benefits from having this tool available as widely as possible outweigh
the disadvantage that some authors may choose to use it, too, for
proprietary software.
