asn1tostruct.py generates three files. Try to teach the makefile that
all three of them depend on the .asn source file to ensure they're
re-built whenever the .asn source file changes.
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