cyrus should be member of saslauth group to access sasldb

Makefile

 all: cyrus-config imapd-config cyrus-imapd-service services
 	rm /etc/passwd
 	mv -v /data/etc/passwd /etc/passwd
+	rm /etc/group
+	mv -v /data/etc/group /etc/group
 	rm /etc/shadow
 	mv -v /data/etc/shadow /etc/shadow
-	useradd -c "Cyrus IMAP Server" -d /var/lib/imap -g mail -s /bin/false -u 104 cyrus
+	rm /etc/gshadow
+	mv -v /data/etc/gshadow /etc/gshadow
+	useradd -c "Cyrus IMAP Server" -d /var/lib/imap -g mail -G saslauth -s /bin/false -u 104 cyrus
 	rm /etc/passwd-
+	rm /etc/group-
 	rm /etc/shadow-
+	rm /etc/gshadow-
 	mv -v /etc/passwd /data/etc/passwd
 	ln -sv /data/etc/passwd /etc/passwd
+	mv -v /etc/group /data/etc/group
+	ln -sv /data/etc/group /etc/group
 	mv -v /etc/shadow /data/etc/shadow
 	ln -sv /data/etc/shadow /etc/shadow
+	mv -v /etc/gshadow /data/etc/gshadow
+	ln -sv /data/etc/gshadow /etc/gshadow
 	tar xf cyrus-imapd-3.2.3.tar.gz
 	cd cyrus-imapd-3.2.3 && ./configure --prefix=/usr --enable-idled --enable-srs --enable-replication
 	$(MAKE) -C cyrus-imapd-3.2.3