вообще-то это совсем другое, см. Dependencies ниже

1. What is Synonym?

Synonym is a Milter extension that offers message archiving capabilities. It runs on top of Sendmail
via the Milter extension and copies all incoming and outgoing email to a predefined mailbox.
The rest of the document offers a step-by-step guide to installing Synonym.

2. Installing Synonym

2.1 Dependencies
        - Sendmail ( >8.11, older versions may work too, I'm not sure I did not check)
        - Sendmail 'cf' (the configuration file needs to be altered and compiling sendmail.mc relies
on this)
        - Sendmail development (the milter headers and libraries)
        - GNU Make