Apache mod_proxy build trickery

I lost a few more hairs building mod_proxy for an existing Apache install. It turns out mod_proxy requires proxy_util.c on the apxs build line.

   apxs -i -c mod_proxy.c  proxy_util.c

Of course the .so builds and installs fine without proxy_util.c, so you think everything is fine until apache pukes with a "missing symbol" error. Frickjacks!