Fair enough, change that depends to depends on "apache2 | httpd".However, now when I install it, for reasons I don't understand, apt-get prefers to install apache2-bin over apache2 (thought it should default to the first item???). This provides httpd and satisfies the depends. apache2 is required for Apache 2.4 configuration, as only it provides /usr/share/apache2/apache2-maintscript-helper.