> This patch adds Mcrypt, and two library dependencies.  Comments
> welcome.

I believe the libraries should be listed in the commit message as new
variables.  Ludo, WDYT?

> +      (method url-fetch)
> +
> +      (uri (string-append "mirror://sourceforge/mcrypt/mcrypt-"

Extraneous newline.

> +    (synopsis "")

Empty synopsis.

> +       ("perl" ,perl)))                 ;for tests

Usually, one puts a space after ‘;’.