Remove unused marco CODEGEN_DUMP.
Use mrb_bool instead of int. This is for portability; based on e767ebf but iv_foreach_func must return int
Use ptrdiff_t instead of int. This is for portability.
Add brances to macro parameter. It may be refactored as GET_UNPACK_{b,c} are used only by GETARG_{b,c}.
For particular environments which has 25 < n < 32 bit int. There is no cost even if you use 16/32bit int targets.
Use size_t instead of int. This is for portability.