IIRC this means you have either libev but the libevent headers installed
or the other way around, not sure anymore. Please check which of the
libev* packages you have installed.
root@debian:~/dect/libdect# dpkg --get-selections | grep libev
libev-devinstall
libev3 install
libevent-1.4-2 install
libevent-core-1.4-2 install
libevent-dev install
libevent-extra-1.4-2 install
root@debian:~/dect/libdect#