If you are still on Trusty you'll need a modern gcc toolchain.
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo add-apt-repository ppa:ubuntu-lxc/lxd-stable
sudo apt-get update
sudo apt-get install build-essential git scons libssl-dev gcc-6 g++-6
sudo apt-get install libboost-filesystem-dev libboost-program-options-dev libboost-system-dev libboost-thread-dev
sudo apt-get install python-pymongo
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-6 1
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-6 1