A bit hacky: the ranap_ies_defs.h is generated together with the
ranap_encoder.c and ranap_decoder.c. See comments in src/Makefile.am and
include/osmocom/ranap/Makefile.am.
We now have the RUA and SUA parts interconnected by the
context ID mapper, and should be able to pass messages back and forward
between both sides.
Unfortunately this touches a bit of everything, but the structures are
all still very much in flux. Hopefully they will start to stabilize at
some point soon...
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