Configure httpd DirectoryIndex

Makefile

-all:
+all: httpd-conf
 	tar xf roundcubemail-1.4.8-complete.tar.gz -C /srv/www --strip-components=1
 	rm /srv/www/index.html
 	install -v -Dm644 config.inc.php /srv/www/config
 	rm /srv/www/config/config.inc.php.sample
 	rm -rf /srv/www/installer
 	install -v -m755 -o apache -g apache -d /var/lib/roundcube
+	@echo "$$HTTPD_CONF" > /etc/httpd/conf/DirectoryIndex.conf
 	chown -v -R apache:apache /srv/www
-	sed -e 's|^.*DirectoryIndex .*|    DirectoryIndex index.php|' -i /etc/httpd/httpd.conf
+
+httpd-conf:
+define HTTPD_CONF
+# DirectoryIndex: sets the file that Apache will serve if a directory
+# is requested.
+#
+<IfModule dir_module>
+    DirectoryIndex index.php
+</IfModule>
+
+#
+endef
+export HTTPD_CONF