Install sa-compile by entering the following commands in the terminal:
sudo apt update sudo apt install sa-compile
Description:
Tools for compiling SpamAssassin rules into C
sa-compile uses "re2c" to compile the site-wide parts of the SpamAssassin ruleset into C code for more efficient processing by spamd or spamassassin.
Homepage: http://www.spamassassin.org/
Version: 3.4.1-8build1
Section: mail