encoding correctness still needs to be verified at this point. At least
they generate some binary output without failing somewhere earlier in
the encoding process - and they don't leave any leaked memory behind,
see talloc_report() at the end of test-ranap.c:main().
So far, we copy-pasted/cherry-picked individual encoder/decoder
functions as the overall ranap_{encode,decode} didn't compile yet.
As the latter is now finally compiling, we can remove those copies and
link in ranap_{encode,decode}.o