phusion passenger on ubuntu 10.04: why apache2-prefork-dev when we want apache2-mpm-worker?

i want to install phusion passenger together with ruby enterprise edition on x86_64 SMP ubuntu 1开发者_开发技巧0.04. the recommended option seems to be

apache2-mpm-worker

but when i run passenger-install-apache2-module

the installation routine of phusion passenger complains

To install Apache 2 development headers: Please run apt-get install apache2-prefork-dev as root.

why do we need prefork-dev here, if we clearly want to run passenger with mpm-worker apache2? any suggestions? is there a worker-dev package?

The worker dev package on Debian & Ubuntu is "apache2-threaded-dev".

Apt-file shows that this installs /usr/bin/apxs2 among other things, so I think this is what you're looking for. By the way, I found this package by using "apt-cache search apache mpm dev".

http://groups.google.com/group/phusion-passenger/msg/b7b2dd8a6561ae36