code: func (c *Class) DefineConst(name string, value Value) {
  	cs := C.CString(name)
  	defer C.free(unsafe.Pointer(cs))
  
  	C.mrb_define_const(
  		c.mrb.state, c.class, cs, value.MrbValue(c.mrb).value)
  }
docs: // DefineConst defines a constant within this class.