configure --with-libevent not causing make unbound-event-install

[A. Schulze]

Am 22.03.2017 um 15:24 schrieb Paul Wouters via Unbound-users:
> 
> When building unbound with --with-libevent support, the make install
> phase should also call make unbound-event-install or else unbound-event.h
> does not get installed and the header file for using the unbound event
> functionality is not available.

Hello,

the same "missing unbound-event.h" happen when building getdns (https://getdnsapi.net)
Thanks for the hint, Paul!

Andreas