Hook mimedefang into sendmail mail filtering

Makefile

@@ -31,6 +31,11 @@ all: mimedefang-service mimedefang-multiplexor-service
 	@echo "$$MIMEDEFANG_SERVICE" > /lib/systemd/system/mimedefang.service
 	@echo "$$MIMEDEFANG_MULTIPLEXOR_SERVICE" > /lib/systemd/system/mimedefang-multiplexor.service
 	systemctl enable mimedefang.service
+	if [ -f "/etc/mail/sendmail.mc" ]; then \
+	    cd /etc/mail ; \
+	    sed "x;/./{x;b};x;/^MAILER(/h;//iINPUT_MAIL_FILTER(\`mimedefang', \`S=unix:/var/spool/MIMEDefang/mimedefang.sock, F=T, T=S:360s;R:360s;E:15m')dnl" sendmail.mc ;\
+	    m4 m4/cf.m4 sendmail.mc > sendmail.cf ; \
+	fi
 	rm -rf mimedefang-2.84
 
 mimedefang-service: