Hello,
if anyone is interested, I've put the sources for my headless c++-client on github:
https://github.com/aholler/crazyflie-client-cpp
Main reason that I've written it, was that I was unsatisfied with the python-client on low speed arm-devices.
The C++-client ends up with around 250kb in size and I find it quiet usable.
Other users of libcflie might have an interest in the updated/modified version you can find there too. Besides some "cosmetic" changes, it now supports read and write of parameters.
Have fun,
Alexander Holler