As a personal note to myself :-)

apt-get install make gcc pkg-config libasound2-dev
wget http://www.pjsip.org/release/2.6/pjproject-2.6.tar.bz2
tar -xjf pjproject-2.6.tar.bz2
cd pjproject
./configure && make dep && make
sudo make install
sudo cp pjsip-apps/bin/pjsua-x86_64-unknown-linux-gnu /usr/local/bin/pjsua 

That’s it!