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.
They are both gone, and pr_pointer_t is now pr_ptr_t (pointer may be a
little clearer than ptr, but ptr is consistent with things like intptr,
and keeps the type name short).
In testing variable fw/precision in PR_Sprintf, I got a nasty reminder
of the limitations of the current progs ABI: passing @args to another QC
function does not work because the args list gets trampled but the
called function's locals. Thus, the need for a va_copy. It's not quite
the same as C's as it returns the destination args instead of copying
like memcpy, but it does copy the list from the source args to a
temporary buffer that is freed when the calling function returns.
