With the release of ROS 2 Beta 2, I figured it’d be wise to update this!
First, you need to have GCC 5.x installed, as there are some C++14 features that GCC 4 lacks that are used in some places.
Additionally, you need to invoke the build system slightly differently.
PYTHONPATH="/opt/ros/lunar/lib64/python3.5/site-packages:/home/${USER}/ros2_ws/install/lib/python3.5/site-packages:${PYTHON_PATH}" src/ament/ament_tools/scripts/ament.py build --symlink-install --cmake-args -DPYTHON_INSTALL_DIR=install/lib/python3.5/site-packages
After that, everything should build just fine (you might need to change the python 3 version in the above line, depending on what python you have installed, and you might also need to change the rosdistro you have if you want the ros1 bridge).