When any will, offered for probate in this state, makes provision for a gift, whether outright or in trust, to or for the benefit of the spouse of the testator or testatrix, such gift shall not be held to be invalid on any of the following grounds: (1) That the amount of any such gift is required to be computed or ascertained by reference to the federal statutes, or any treasury regulation issued thereunder, authorizing the allowance of a marital deduction in the computation of the federal estate tax or by reference to determinations or settlements of any kind whatsoever, whether by agreement, litigation or otherwise, in the proceedings for the assessment of said federal estate tax in the estate of such testator or testatrix; (2) that any such gift is required to be satisfied only by property which qualifies under said federal statutes, or such regulation, for such marital deduction; or (3) that any property allotted to the satisfaction of any such gift is required to be allotted at the values determined for such property, whether by agreement, litigation or otherwise, in such proceedings for the assessment of said federal estate tax or at values to be determined in any other reasonable manner.