etc.c: clear `mrb_value` if `sizeof(void*)` is bigger than `sizeof(mrb_float)`.
@@ -159,6 +159,9 @@ mrb_word_boxing_float_value(mrb_state *mrb, mrb_float f)
union mrb_value_ v;
#ifndef MRB_USE_FLOAT_FULL_PRECISION
+#if defined(MRB_64BIT) && defined(MRB_USE_FLOAT32)
+ v.w = 0;
+#endif
v.f = f;
v.w = (v.w & ~3) | 2;
#else
