Hello,

The following patch adds nauty to maths.scm. Upstream doesn't provide
any install target, so installation is rather rough. In particular, it
creates a lot of executables. For the record, Debian prefix all of them
with "nauty-" (except for the main one: "dreadnaut"). I sticked to
upstream names.

There is no missing module, I promise. ;)

Feedback welcome.

Regards,

-- 
Nicolas Goaziou