For running Weston you need to have $XDG_RUNTIME_DIR in your environment,
directory must exist and have correct permissions. If you are not using systemd,
it will not be created automatically, you can create it using your shell,
add these lines to ~/.bash_profile:
# wayland
export XDG_RUNTIME_DIR=/tmp/.runtime-${USER}
mkdir -p "${XDG_RUNTIME_DIR}"
chmod 0700 "${XDG_RUNTIME_DIR}"