Change `SIGNIFICAND_*` to `SIG_*` and `EXPONENT_*` to `EXP_*`. This makes things more consistent with `libm`, and terseness is convenient here since there isn't anything to confuse.
Change `SIGNIFICAND_*` to `SIG_*` and `EXPONENT_*` to `EXP_*`. This makes things more consistent with `libm`, and terseness is convenient here since there isn't anything to confuse.