Installing apxs2 on Ubuntu Server

Ah, another happy Saturday doing sysadmin crap. I had a lot of trouble scaring this information up, so maybe a blog post will help the next person. In order to get apxs2 installed on Ubuntu (and probably Debian) you must install apache2-threaded-dev (or possibly a non-threaded equivalent). You will start to care about that if, for example, you want to install Apache2::Cookie, which depends on APR::Request, which is messy. But oh, wait, that module is broken and won't install anyway. If I figure out how to fix it, I'll probably post again for the same imagined posterity... currently the thing says my perfectly good apache2 binary is bad. Anyway, regardless of that problem, you will also be unable to install APR::Request without an apxs2 binary, and you'll have a hard time finding that on Ubuntu unless you sudo apt-get install apache2-threaded-dev (or equivalent).