configure
is checking whether it will be possible for the package build
to link libevent
. For that it needs see that libevent
development
dependencies are satisfied. It checks not only that libevent
itself can be found
for linkage but that the header <event.h>
(exactly like that) can be
found for compilation.
For configure
to succeed you must make sure that:-
event.h
from your libevent
package will be found in the default or
configured include-search paths of the compiler.
The libevent
binary will be found in the default or configured library-search
paths of the linker.
Near the top of the HowTo that you
have referred to you will see that configure
accepts a parameter
--with-libevent=libevent-prefix
that can make this easy. ./configure --help
says:
--with-libevent=prefix Specify where libevent is installed
For your ubuntu system the short answer would be: install libevent-dev
from
the package manager. In Ubuntu you could also install pgbouncer
from
the package manager, but perhaps you want the latest version.