After determining the dependencies, I was finally able to compile fwknop-2.0.0rc server on a 32-bit Ubuntu Server 10.04 virtual machine:

sudo apt-get install libgdbm-dev libgpgme11-dev libpcap0.8-dev autoconf build-essential m4

./configure --disable-client --with-gpgme
sudo make install

That didn't work for me on a 64-bit Ubuntu Desktop 10.04. Can fwknop-2.0.0rc compile on 64-bit? Any idea what I'm missing?