The GNU Autoconf Archive is a collection of more than 450 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. WWW: http://savannah.gnu.org/projects/autoconf-archive/