This is part of the work for #26 (Record resource pointer with builtin
function data). Currently, the data pointer gets as far as the
per-instance VM function table (I don't feel like tackling the job of
converting all the builtin functions tonight). All the builtin modules
that register a resources data block pass that block on to
PR_RegisterBuiltins.
This will make it possible for the engine to set up their parameter
pointers when running Ruamoko progs. At this stage, it doesn't matter
*too* much, except for varargs functions, because no builtin yet takes
anything larger than a float quaternion, but it will be critical when
double or long vec3 and vec4 values are passed.
I never liked that some of the macros needed the type as a parameter
(yay typeof and __auto_type) or those that returned a value hid the
return statement so they couldn't be used in assignments.
The api hides all the gory details of message buffer setup and usage
(particularly the differences between writing and reading). Most
importantly, the api provides a safe way to read and write binary data
(always little endian).
