The functionality for `...` and `np.newaxis` is there in IRRT, but there
is no implementation of them for @kernel Python expressions because of
M-Labs/nac3#486.
Achieved through defining all the needed Exception ID constants at link
time.
Secondly, since `Exception` is `size_t` dependent, `__nac3_raise()`
takes an opaque pointer to `Exception`, unless IRRT is compiled into
32-bit and 64-bit separately with a defined `size_t` type.