I am currently working on adding a small number of FreeBSD ports for CloudABI tools and libraries. Some of these (e.g., Binutils) use Autoconf. Though support for CloudABI has been added to config.guess/config.sub, the FreeBSD ports tree overwrites these files with custom versions automatically.
This change brings in the latest version of config.guess and config.sub from upstream, but leaves the small number of local modifications that we have intact.